Astrophotography Equipment

Imaging location:   I image in northern RI, about 10 miles northwest of Providence, and about 50 miles away from my hometown near Boston.  The light pollution is moderate, and there is skyglow near the southeastern horizon from Providence.  The Milky Way is faintly present on most nights, the average LVM is about 5.5, and the site is class 5-6 on the Bortle Dark-Sky scale.  Unfortunately, my seeing only averages around 3", and sometimes worse, at this site.

Mount and related accessories: 

Initially, I used a Losmandy G11 with Gemini GOTO system, upgraded to the Gemini L3 v1.13 EPROM.  This is a good mount for the money, but I noted inconsistent tracking once I added the FSQ106 (which is a relatively heavy scope), especially near the meridian.  This resulted in lost imaging time due to many subs with less than perfect stars.  I spent many hours tweaking the G11 but finally concluded that I needed an upgrade.  In the summer of 2007, I moved to the Takahashi NJP mount with Temma 2, shown above, which has been a great performer.  Chuck Faranda has kindly created a driver for the NJP Temma system that allows computer control via ASCOM.  The Yahoo Losmandy Group is a great resource for the G11, and the following website also contains useful information.  The Yahoo Takahashi Group is a great resource for Takahashi products, including scopes and mounts.  Other items/features present in the photos include JMI Wheeley Bars (a great backsaver!), and a red tool cart from Sears (a convenient way to store, transport, and organize equipment both during and after the imaging session).
 

Telescopes:

Takahashi Sky90 (sold): 

The Takahashi Sky90 shown in this older photo above is attached to the Losmandy dovetail plate system with a set of Parallax rings, which fit perfectly and are beautifully manufactured.  There are miscellaneous items such as the f4.5 field flattener (highly recommended), spacers, T-mount, and the Camera Angle Adjuster in the imaging train- please consult with appropriate vendors to tailor the Sky90 components to your needs.  In the image, the Camera Angle Adjuster is first, followed by the focal reducer, followed by the CA35 adapter and then the wide T mount, which connects to the filter wheel.  The True Technology Slim Design Filter Wheel uses the SCTM-T-LR and SCTM-TF adapters (available from Adirondack Video Astronomy).  The camera connects to the other side of the filter wheel via the T thread.  The Backfocus distance chart provides a good starting point for determining the correct distance between the CCD chip and the focal reducer, although some experimentation is required to get the best results (backfocus is 72 mm for this arrangement, which includes the 17 mm flange to CCD chip distance of the SXV-H9, or the 28mm flange to CCD chip distance of the Maxcam CM10).  The curvature map of my Sky90 at f4.5 with the Maxcam CM10 camera (10mm x 14.9mm chip size) is shown here.


Takahashi FS102 (sold): 

The Takahashi FS-102 is shown here.   The pole that is used to hold up the weight of cables was purchased as a hanging flower basket item at Home Depot a few years ago.  NOTE: I have arranged my cables differently after this photograph was taken (see below under "Cable Management").  With the TOA-130 focal reducer, the f ratio is f6.  In this image, the Camera Angle Adjuster is first, followed by the TOA-130 focal reducer, the Feldstein #4 adapter (T-thread to FSQ-106, item TCD0008 at Adirondack Astronomy), and then the Astronomiks filter drawer holder (which is 21 mm thick).  This allows me to insert a 48mm IDAS-LPS filter into the imaging train when doing LRGB work.  The True Technology Slim Design Filter Wheel uses the same SCTM-T-LR and SCTM-TF adapters as mentioned above.  The Maxcam CM10 is connected to the other side of the filter wheel via the T thread (an SCT to T adapter is used inside the CM10 flange, available through FLI).  The backfocus for this arrangement is 83.9mm, which includes the 17 mm flange to CCD chip distance of the SXV-H9, or the 28mm flange to CCD chip distance of the Maxcam CM10.  The curvature map of my FS102 at f6 with the CM10 is shown here.  The corresponding curvature map of my FS102 at f8 with the CM10 (i.e., without focal reducer) is shown here.


Takahashi FSQ106N: 

I purchased the FSQ106N (shown above) in the summer of 2006 for subsequent use with the STL11K camera, which has a 24 x 36.1 mm array.  The above set up is not used anymore, since I now place the FSQ106N on the NJP mount, and I guide with the ST402/60mm guidescope piggybacked on top (see below for image of ST402 with 60mm guidescope on the VC200L, with more details at the end of this page).  The FSQ106 provides a very flat field that easily accomodates the large chip of this camera, at the fast speed of f5.  I had considered even faster astrographs (like the Tak Epsilon 180 and the ASA Newtonians), but I was not convinced that their focusers were robust enough to prevent flexure, and I wanted to minimize fiddling and maximize imaging time.  The FSQ is always ready to go, produces nice round stars, and has great focuser that easily accomodates my Robofocus.  I had to adjust the Camera Angle Adjuster in order to minimize play in the system, which caused stars to be elongated in the corners of some images.  Here is my post describing this procedure on the Takahashi Yahoo site (I found this to be a very straight-forward adjustment, but if you decide to do it, it is at your own risk).  Also, Frank Barnes describes a procedure to tighten up the focuser tube in order to reduce play that can lead to tilt.  His procedure may be downloaded here, and it is mentioned on the Takahashi Yahoo group as well.  See the camera section below for details regarding how I attach the STL11K camera to the FSQ106.  Please click here for the curvature map of my FSQ106 and STL11K.  See below under "CCD cameras" for details regarding my setup with the FSQ106N and the U16M/FW50-7S.


Vixen VC200L: 

I wanted a lightweight, longer focal length scope for imaging galaxies and planetaries in greater detail and decided to purchase the Vixen VC200L, which is a modified Cassegrain design (shown above).  This scope has an 8" aperture and a native focal length of 1800mm at f9.  I mounted it with Parallax rings, and I attached a Losmandy dovetail plate on top to mount a 60mm guidescope (227mm at f3.7, with the ST402 autoguider) described more fully in the "Autoguider" section below. 

To attach the Robofocus (shown below), I simply used the metal bracket provided by Technical Innovations and shaped it as required to accomodate the focuser lock screw as shown below.  I used a few washers under the lock screw to prevent it from actually locking the focuser tube in place.  I find this to be a simple and very sturdy arrangement that permits accurate focusing without noticeable play.

Modifications to the VC200L:  I have made two modifications/adjustments to the VC200L which have improved its performance.  These are 1) Reducing the thickness of the spider vanes holding the secondary by using a Makita 4" grinding wheel as well as a metal file (lots of tiny metal particles fly around when you do this, so it's important to wear a mask and eye protection, and you do this at your own risk).  This procedure is not for the faint of heart and takes about two hours of hard work.  It requires removing the front spider vane assembly (and obviously removing the secondary) from the OTA, since you definitely don't want mirrors/optical elements anywhere near the metal filings.  The reward for doing this is thinner vanes that completely prevent the problem with square shaped stars and also permit better resolution of smaller stars since less light energy is being diffracted.  2) Removing the mirror cell for cleaning, and at the same time loosening the 6 metal brackets/screws that hold the mirror in its cell, since these were too tight and prevented any mirror movement (you want the mirror to move about 1 mm in any given direction to prevent asymmetric stress that could cause optical aberrations, including triangular stars).  I believe that this step is critical, in order to avoid problems with triangular-shaped stars that are characteristic of pinched optics.  I found this website very helpful during this process.

The VC200L Yahoo site is a great resource, especially for files related to collimation, which is critical for obtaining the best performance from this scope.


CCD cameras:  
1.  SXV-H9 monochrome CCD camera (sold) from Starlight Xpress.   This ABG has good sensitivity and very low dark current, making dark frames generally unnecessary.

2.  MaxCam monochrome CM10 camera from Finger Lakes Instruments, with the Kodak full frame 3200 ME (microlensed) chip (this chip was subsequently removed and placed into the Apogee U32 platform as described below).  I purposely requested not to have a cover slip, in order to avoid reflections from brighter stars (and to avoid the slight decrease in light transmission seen with the coverslip in place).  This NABG chip is very sensitive, with a reported QE for Ha light of 85%.  UPDATE, 7/27/07:  I have been having problems with horizontal bands due to clocking issues with this camera, which does not have a full frame buffer.  I e-mailed FLI in early June for details regarding an upgrade by transferring my chip into the new Microline platform (which is supposed to have a full frame buffer).  I was told that they would get back to me with pricing "soon."  No further response, and after several weeks I called again to discuss.  I was again told that I would be provided with information "soon."  After two months without a definitive answer about availability or pricing, I called Tim Puckett at Apogee Instruments to see if he could help.  Tim was very responsive, and I upgraded my KAF3200 chip into the U32 platform (details below).  Time between my first phone call to Tim and having the upgraded camera in my hands was about 3 weeks.

3.  STL11000M, class 2 chip (sold) from Santa Barbara Instruments Group.

I purchased the STL11K in November 2006 for use with the FSQ106.  It is coupled to the FSQ106 through the use of the Feldstein #6 adapter, which provides a simple and strong connection.  I also use a 72mm Tak extension tube (about 2.25" long), part number TKA2350, in order to rack the focuser in as much as possible so as to minimize focuser sag due to the weight of the camera.  I loaded the built-in filter wheel with unmounted 2" filters to minimize vignetting (LRGB filters from Astronomiks, and the Ha 7nm filter from Baader).  This camera is great fun to use!  Images of this set up can be found here and here.

4.  Apogee Instruments U32 Camera.  The details of this camera may be found here.  The camera is beautifully designed, with a pleasing blue anodized surface, 4 cooling fans, a robust cooling system (50 degrees C below ambient), a full frame buffer (32 Mb), and several user adjustable controls, including fan speed.  The opening contains C threads, and I purchased a C to T female adapter from Edmunds (part #NT53-483) in order to attach it to the Starlight Xpress USB filter wheel  (described below).

5.  Apogee Instruments U16M camera.  The KAF16803 measures 4096 x 4096 pixels and is a very clean, low dark current chip.  The camera is beautifully made, cools to -40 C delta in 30 minutes, and is attached to the FW50-7S filter wheel (7 slots for 50 mm Baader square filters, described below).  The detail of this large chip camera may be found here, and an image of this setup is seen below:




The imaging train for this setup is based upon the following considerations.  With the focuser tube fully retracted into the scope, the backfocus of the FSQ106N is 120mm, as measured from the end of the CAA (with the 72mm black ring adapter removed so that the opening is 92mm).  I wanted the focuser tube to extend outward only about 20mm, to avoid flexure problems due to the weight of the U16M and filter wheel (20 mm would give me plenty of room to obtain V curves using Focusmax, for instance).  This means that I have 100mm left (120-20) to be made up by the camera, filter wheel, and adapters.  The optically corrected flange to chip distance of the U16M D07 model is 1.008", the optically corrected thickness of the FW50-7S filter wheel is 0.900", and the thickness of the adapter plate that connects the filter wheel to the camera is 0.250", making a total of 2.158", or 54.81mm.  But I want to make up a total of 100mm, which means that I still need 100-54.81mm, or about 45mm, in extra adapters.  I achieved this with two other adapters 1) a 20mm long adapter made by Ashley Stevens at Precise Parts, which screws into the Apogee filter wheel on one end (3"- 24 TPI) and then has a 92mm (female) opening on the other end, and 2) a 25mm long spacer ring (92mm opening) from Takahashi (part # TAR0130, Texas Nautical Repair), which screws into the 92mm Precise Parts adapter on one end, and the CAA (92mm) on the other end.  This gives me 54.81+20+25 = 99.81mm, meaning that my focuser tube will extend out by 120-99.81mm, or 20.19mm (close enough!).

6.  SBIG ST8300.  The details of this camera may be found here.  The camera is small, lightweight, and a perfect fit for my VC200L (image below). 



The ST8300 camera is shown above, attached to the VC200L in f6.4 configuration.  The imaging train shown above is as follows (from right to left):  M60 adapter (included with the Vixen focal reducer), M60-M57 adapter (Borg #7901), rotator (Borg #7352), M57 to male T thread (Borg #7522), Starlight USB powered filter wheel (T thread female on telescope side and T thread male on camera side), ST8300 camera.  Alternatively, I use a C to T adapter (Edmund's #NT53-483) to attach the U32 camera to the Starlight filter wheel when using this scope.


Filter wheels: 
1.  True Technology Slim Design Filter Wheel (not used anymore). 

2.  The STL11K has its own built-in filter wheel.

3.  Apogee FW50-7S for the U16M (50mm square filters).

4.  Starlight Xpress USB powered 5 position wheel for 2" filters.  I use this in conjunction with my ST8300 camera as well as my Apogee U32 cameras.


Filters: 
1.  For the True Technology Slim Design Filter Wheel (used for U32 and SXV-H9 cameras):  Astronomik 1.25" filters (Clear, Ha 12nm, Ha 6nm, OIII, R, G, and B).  I like these filters because they are durable and reasonably priced.  For Ha work, I initially used the 12 nm bandpass filter with the Sky90/SXV-H9 set up at f4.5 with good results.  When I moved to the FS102/U32 set up at f6, I wanted the narrower Ha bandpass (6 nm) in order to obtain more contrast while at the same time minimize blooming with the U32 (NABG).  

2.  For the STL11K (internal filter wheel), I use unmounted 50.8mm filters to minimize vignetting (LRGB filters from Baader, the 7nm Ha filter from Baader, and the 8.5nm OIII filter from Baader).  I have been very impressed with the narrowband Baader filters- they have minimal problems with halos, they yield great contrast, and they are a terrific value when compared to much more expensive filters on the market.  Given how expensive this hobby already is, and given the excellent performance of the Baader narrowband filters thus far, I simply cannot justify spending even more money on filters.  Johannes Schedler also uses Baader narrowband filters and has posted a review of the Baader LRGB set on this website.

3.  Because I like the Baaders from my experience with the STL11K, I purchased a set of 50mm square Baader filters for the U16M from Alpine Astronomy- LRGB, HII (7nm), OIII (8.5nm), and SII (8nm).

4.  For the Starlight 5 position, 2" filter wheel, I use 2" mounted Baader filters (LRGB and 7nm Ha).


Autoguider:

I used an SBIG STV (sold) with the e-finder for several years, but later switched to an SBIG ST-402 (shown below), which is more sensitive and permits remote operation through Maxim.  Like the STV, I have used the ST-402 with the e-finder, and this arrangement has always provided an excellent choice of guidestars.  However, the image scale of this arrangment was 18.5"/pixel, which is insufficient for guiding the VC200L (image scale 0.78"/pixel at f9 with the U32 camera).  In order to solve this problem, I remembered that I had an old finderscope from my 23 year old Meade LX 2080 8" SCT (remember that scope?).  This finderscope has a great 60mm aperture, 227mm focal length objective (f3.8) and results in an autoguider image scale of around 8.1 "/pixel when used with the ST402.  Below is shown how I attached the guidescope to the mount, including hose clamps to ensure stability (clamps attached to 6" metal plates from Home Depot on top and bottom; guidescope OTA protected by felt).  Note that the ST402 itself is not physically attached to the guidescope, but fits into the back end of the guidescope using 2, 20mm T spacers to provide the correct backfocus and to eliminate outside light.  Fine tuning of focus is easily achieved by turning the objective at the front end of the guidescope, and then tightening the lock ring to ensure stability.  This arrangment is rock solid and has thus far guided beautifully, without a hint of flexure:

Focuser:  A Robofocus unit which permits extremely accurate and rapid focusing in conjunction with Focusmax software (used through MaximDL/CCD).


Cable management:
Proper cable management is a critical aspect of imaging throughout the night.  I use plastic cable wrap from a local electronics store for this purpose.


Computer:

Check out the Links page as well for additional tips/resources:  Links

All Images Copyright Steve Cannistra