Oct. 2010

This month I finally  broke down and purchased a wide field of view camera, an Orion StarShoot Pro V2 color camera, for  imaging those large objects.  My Meade DSI color camera still works fine but I got tired of building mosaics of big objects like the Pleiades, Andromeda, Rosette nebula, and the like.

The smaller pixels and large format makes a big difference in the quality of the images.

I did however run into one problem, that  being vignetting. The DSI, having such a small FOV didn't suffer from that  problem.
  I ended up  with  a hot spot in the center of the image and the outer edges were darker.  To eliminate the vignetting I had to  apply flats during the processing of the raw images.  I had been shooting my flats during the day after taking the images by placing two layers of T-shirt material over the end of the OTA and shooting flats.

I had applied these flats  to my images but got all kinds of odd results form reverse vignetting , light edges and dark central region to a gradient problem across the image.  I beat my head against this for a number of weeks and finally decides that  there has to  be something wrong with the flats. Perhaps stray light leaking in or something. 

Jan 2011

The problem I had with  my previous flats prompted me to  build a light box to  use in shooting them. I had read about them but didn't think I needed  one.

I made my box out of 1/4" foam core board readily available at Staples and othe4r office supply houses. The box is a 12" cube with  one end having a 10" hole cut in it  which fits the dew shield of my SN8 . The segments are held together with  the ubiquitous Duct tape . I used blue painters tape to  fasten the outside back cover which  should allow me to easily remove it  should I need to  replace a bulb. 

I put one 12v 25mA mini lamp ( purchased at Radio Shack) in each corner of the back that  fits over the dew shield. I placed another panel with  a 10" hole over the back  about 3/4" from the one holding the bulbs. This provides a bit more stability to the box when slid over the dew shield.

I power the lamps with a 9V source to  keep the brightness down.

I have only made one set of flats with  it so far but have noticed that  there is a marked improvement in the quality of the final image. I still need to experiment with  the flats to  insure I get the best ones.

Oct 2 2013:

My Orion Star Shoot Pro  color camera bit the dust. It won't talk to the computer. I'm not sure it can be fixed , though I have some acquaintances that  might be able to take a look at it.   I got about three good years out of it. Time to upgrade!!

Upgrade I did. Purchased a almost new (still under warranty) SBIG STF8300c one shot color camera. The camera has relatively small pixels, 5.4 microns, which allow it to get finer details than the SSP which had larger pixels. The camera also has TEC (Thermo Electric Cooling) that  is regulated to keep the CCD at a preset temperature. This feature keeps the read out noise to a minimum. The warmer the CCD gets the noisier the image will be.

I've taken a couple of test shot with  the camera and am very pleased with  it's performance.

The table below lists the specifications for the STF-8300 camera. Specifications are typical and can vary from camera to camera and are subject to change without notice.

STF-8300 Typical Specifications

March 2014

     Time to spend some more money. I've been using the SN8 for all of my imaging to date. I thought it would be interesting to see what  kind of images I can get with the SBIG and the ED80. The problem is that  I'm using the ED80 as a guide scope so I needed a replacement. The choice I made was the Orion 8891 Mini 50mm Guide Scope .  The plan was to use the 50mm and the DSI pro camera for guiding which would allow me to mount it on the 8" Newtonian or the ED80. To my pleasant surprise, the combination of DSI and 50mm scope worked perfectly. The 50mm has a wide field of view which makes it easy to lock on a star for guiding. The DSI Pro is sensitive enough to pick up a large number of stars in the FOV and the guiding is spot on.

My next trial will be to hang the SBIG on the ED80 and see what I can image. I'll wait for a little while longer for he weather to warm up, though.