Astronomy

From top to bottom:

Guide Scope:
Orion ED80 (80mm f/7.5, 600mm FL semi-apo) with Losmandy guide rings, and RoboFocus motor.

Guide Camera:
The camera is a Meade DSI2Pro with Outback cooler.
I've taped the stupid filter holder with aluminum foil inside a sandwich of gaffer's tape to be sure that there is no light coming in from the sides. The filter holder comes with a 1.25" nose that is actually a T-mount adapter. So, I use a 2" to T-thread adapter.

The FOV of the DSI2 with the ED80 is about 36' x 28.1' with an image scale of about 2.88 arcsec/pix.

I recently started using it with cheap SAC 0.33x focal reducer ($65 from OPT) on the DSI2 to speed up the optics and to substantially widen the field of view. With the reducer, I get 198mm f/2.5 with 85' x 109.1 arcmin FOV, but an image scale of 8.74 arcsec/pix, probably not ideal for guiding, but it makes a good eFinder in that configuration.

With an Orion 2x APO Barlow, it yields a darker f/15 focal ratio at 1200mm FL. Image scale is 1.44 arcsec/pix and 18' x 14' FOV.

You can see AstroZap dew heater straps on the Orion.

Main Scope
The main scope is a TEC140mm (5.5") f/7.0 APO. This scope has near perfect optics and is a joy to have.
It's mounted with the TEC rings with 2 Losmandy 13.5" DUP Universal plates top and bottom (purchased from OPTCorp). The universal plates only accommodate one screw that matches the TEC rings. So I need to drill some holes in it them for a more secure mounting to be able to use the outer two holes in the TEC rings.

The TEC also has a RoboFocus motor, but I only have one controller - but I only have to really focus the guider about once every three months or so - it stays in focus enough for guiding, finding, and centering. So the controller is usually connected to the scope. Ideally, the robofocus controller would support multiple focusers.

The TEC140 has a wonderful FeatherTouch 3545 focuser with a special collet-style 2" adapter at the end. I have to say that I really like the collet-style adapter. It is very easy to use with one hand and it is very secure. It also ensures that the camera stays centered in the optical path, unlike with the compression ring or other techniques. I actually use the graduated markings on the focuser to get a rough focus when I change cameras. I didn't think the markings would be that useful, but I'm glad they are there.

I usually use my Canon 20D unmodified on the scope until I can save up for an SBIG full frame system. However, I use my DSI2c that I won in a raffle to drift align the mount through the main scope. I have found that the Losmandy guider rings are slipping sometimes during the process and throwing off my settings. I'm thinking of getting some guider pads from Ken's Rings to see if that will stop the guide scope drifting.

The imaging train shown here is two 2" long extenders coupled to the DSI2c. I should measure and post the distances for all these configurations, but I haven't gotten around to that yet.

With the Canon 20D and a single 2" extender, I can set the focuser at about 43mm-45mm on the focuser markings and be close enough to be able to do the focusing on the computer.

When the TEC Field Flattener arrives, I will use the Astro-Physics 67RLEOS adapter ($90) with the Canon and I will probably require another kind of adapter for use with the SBIG ST10XME.

The finder scope is mounted backward so that it didn't nterfere with the guide scope and so that I could get my head close enough to it when all the camera gear is attached. Even still it is a little difficult. I like the AP 8x50 illuminated finder a lot. It has a heater strap too. The rear eyepiece cap is very loose and is not a good design for this, as it keeps falling off. The front cap is very tight and I almost always move the finder when trying to remove the front cap.

I mount the bottom Losmandy plate to a Casady 8" saddle. A 3 foot x 1/8" aluminum bar is bolted to the top of the AP mount with 1/4 20 screws that have plastic knurled knobs. This serves as a point where I can tie-off the cables. I have found that tying off the cables out closer to the cameras prevents the cables from catching on the mount.

Mount
The mount is an AP1200 CP3 attached to a 10" pier via a 360 degree rotating adapter plate (can't remember the maker - starts with an "M").

I love this mount. I've been able to take 10 minute unguided exposures of Pluto with it in 30 knot winds. I've done a lot of imaging in 20+ knot winds and the wind has never even so much as registered on the guider (not shaking the scope).

I have 2x18lb Casady weights and a 7lb Casady weight, but in this configuration, you can see that I only need the 25lbs not even half way down the counterweight bar.

The Astro-Physics 10" portable pier is a simple but good design and it is very stable.

I have a Finger Lakes filter wheel, but that isn't installed yet. I plan to do narrow band imaging with that eventually. In the meantime, I have one of the filter holders blocked from light to be able to automatically take darks with DSI and DSLR cameras. It is heavy and I don't have adapters for the DSI cameras with it.

I have a wide velcro strap going around the pier that holds a 7 port USB high-speed 2.0 hub and the robofocus controller.

I keep a sheet wrapped around the base of the mount to prevent dew and stuff from getting on the hub, the mount's CP3 controller box, and other electronics.

I have a Phoenix 40amp DC power supply in a box under the table as well as the Robofocus AC power controller. I can turn off the Canon camera and other equipment remotely using this configuration.

I leave a n IBM laptop under a towel out by the scope when I start imaging and use Remote Desktop to terminal serve into the IBM from inside the house. Almost everything can be controlled from there, once I have set things up.

To set up, I uncover about 5 different covers that I have over the gear to protect from the elements and UV. It takes about 15 minutes from opening the back door to do that to the point where I am back inside the house imaging.

I will be ordering a POD dome pretty soon.




I have a DewZapper dew controller with temperature sensor. I



This is me in the backyard between the house, the fence, and the orange tree. Between the three of those obstacles, I don't have a very great area of the sky to image in. In addition to that, my neighbor has a back porch light that she turns on that is almost due east and about 40 feet away. North of me is a streetlight. There used to be a 30 foot amber tree, but I couldn't see polaris through it so I cut it down (besides, I didn't like those little spikey balls that fall off of it).


(DaveImagingTEC140.JPG)

I got this in 2003 and sold it a few years later so that I could get the AP1200.

(telescope.jpg)