Posts Made By: David Keller

I'm not trying to be insulting here but while everybody else is giving praise, I'm thinking "What went wrong with this picture?" Compare the Saturn images on 10-22 and 11-8 vs. the images on 11-14 and 11-20. The planetary disk has multiple edges (or ghosting?) in the 11-14 and 11-20 images. Detail in the rings is nice but I think the 11-8 image has the best overall fidelity so far.

Help Ron! What's causin' all this?

Dave Keller

Tom,

Your image definitely suggests that the camera gain setting is too high (oversaturated). Go into the camera controls and disable the "auto" setting so that you can manually adjust the gain. Once the gain is down enough, then you can refine the focusing. Use a Barlow or Powermate to increase your focal length which will increase the image scale and resolution (if the skies are stable enough). A 3X Barlow will get you up to f/18.9 and 4800 ml focal length (equivalent to 96X by photography rules). You may need to get a flip-mirror unit to help center the planet on the CCD chip at this magnification. A 4X or 5X Televue Powermate can be used but the planet size may get too big to fit and keep on the chip. Taking prime focus pictures with the 10" f/6.3 won't bring out all the fine detail possible because the photographic magnification is too low (~ 32X).

As for processing software, there are several shareware programs available. "Avi2bmp" is a shareware program that allows you to view individual frames in an avi file, pick the best, then save those as bmp files for stacking. "Registax" shareware can also process avi files into bmp files and do stacking at the same time. Registax is much better than Astrostack because it has an excellent "wavelet" image processing algorithm which can bring out details that Astrostack can't (or at least I can't). Final color processing can be done in Adobe Photoshop (or equivalent) where you can also convert the image to jpeg format to decrease file size. I prefer to select the frames in Avi2bmp, then align/stack/sharpen some in Registax with final touches done in Adobe Photoshop 5.0 LE.

Dave

Ah, the sweet image of success! Your on a roll now.

You certainly aren't kidding about poor seeing conditions (in general, not specific to the image). The Indiana region has been virtually all clouds since last week in October. Only two clear nights have been steady in that time period. All other clear nights (perhaps 5-7) had so much instability that focusing was impossible.

Dave

It's "no contest"; the winner is the Takahashi FS-102 when buying brand new. About the only refractor that is better optically would be a used TMB 100/800 or TMB 105/650 in the Vixen tube. These versions of the TMBs do occassionally pop-up at under $2000 on Astromart. A used Vixen FL-102S (f/9 fluorite) can easily be had for under $2000 and can give the Tak a run for the money in the optics category but it falls short on mechanics.

Dave Keller

Very nice, smooth result. Just the way I like it. A 20% batting average on stackable frames is what I call normal viewing conditions here in Indiana. If my knowledge is correct, an IR-blocking filter doesn't help on short exposures used in Lunar and brighter planetary imaging. Hopefully, somebody with greater experience will chip-in on this issue.

Yes, it would be nice if we could get stable skies like what Yu Gu and Florida receive.

Dave Keller

I do have what could be called "second-hand" experience. I purchased a used 6" f/5 Telescopics primary on Astromart that had been refigured by Dick Wessling (Pines Optical Shop in Ohio). The Foucault analysis of the mirror before refiguring was 1/2.4 wave (PV) and I think the RMS was just within diffraction limited tolerance (don't have data sheet with me at the moment). The original owner said that it performed poorly but now works great after the refigure; I have verified the excellent performance. I ran a search on sci.astro.amateur for Telescopics mirrors and based on sampling some of the results, nearly everybody had to have the mirror refigured (this was likely long after the Telescopics brand name dissappeared as a business).

Since my search was limited, I can only recommend that you verify performance before plunking down the cash on a Telescopics mirror. If the mirror has not been refigured, the chances are good that it could be of poor/marginal quality.

Dave Keller

I know this isn't a refractor but the most obvious, biggest grab'n'go scope I can think of is an 8" Portaball. It does need assembly out in the field but you only need to make a minimum of three trips back and forth to the car when loading/unloading:

1. Collapsed Portaball - this contains the shroud, upper cage assembly, light shield, finder, eyepieces (if stored in plastic cylinders), barlows, and collimation tools.

2. Chair to sit in.

3. Portaball Base + Truss Rod Carrying Tube.

This can actually be done in two trips for some people. The 10" Portaball could also qualify because it uses the same sphere as the 8". I don't think the larger Portaballs qualify because they really should be moved with the cart due to the heavier weight.

When it comes to refractors, I don't have an Alt-Az mount set-up to give a good recommendation yet.

The 8" Portaball does pop-up used in the price range you are talking about on rare occasions.

Dave Keller

Stephen,

Since you are doing webcam photography with a Philips Vesta Pro, Registax is an excellent first step for doing alignment, stacking, and sharpening on planets. Registax is freeware so that will cost you nothing.

You will still need another program or two in order to adjust color balance, saturation, and tweak the sharpness (or add slight blurring to remove graininess imparted by Registax). Adobe Photoshop 5.0LE is often bundled with new hard drives (I got this with a Maxtor hard drive) and will solve color balance and blurring issues. The one problem that Adobe Photoshop 5.0LE cannot due is realign RGB elements. Many webcam imagers run into the problem of obtaining planetary images that have a blue limb. This is apparently caused by the atmosphere (I wonder if the color camera is also partially responsible). A shareware program called "The Gimp" supposedly can split a bmp or jpeg color file into RGB components and then realign; I have not tried this software yet but it sounds like it can do all the other color adjustments too. There are Photoshop clones that cost ~ $100 that should be able to do this but I have not tried these either. AstroArt 2.0 can do RGB realignment and costs $150. I just acquired this but haven't learned how to use the software yet. AstroArt 2.0 does not have a good instruction book but there is an AstroArt Yahoo group where you can get help (if not in this group). K3CCD Tools might be able to do RGB realignment but I don't know for sure (this is a shareware program).

Dave Keller

The Canon G2 can work but it's limitation is the 15 second maximum exposure length. Thus, deep sky shooting will be limited to brighter objects and you will have to stack several frames to increase the S/N ratio. Lunar, planets, and brighter globular clusters/nebula/galaxies should be no problem when using the Scopetronix adaptors and eyepiece projection. The Sony PlayStation One 5" LCD monitor definitely helps with focusing; the G2 screen is too small. The LCD monitor costs ~ $130 new at Toys'R'Us and requires a stereo AV patch cord from Radio Shack (~ $5) to connect to the camera. You will need a 120V powersource to run the LCD monitor.

I have just started dabbling in this with the G2 + Scopetronix 40 mm Plossl/Adaptors on a TMB 100/800. Weather has been too crappy to spend serious time on this but I was able to bring-out some of the outer nebula details in M42 with 7 stacked frames shot at ISO 200. A flat field light box will be needed because full resolution photos have some vignetting. I also have 8" and 9.25" SCTs and a 12.5" Portaball to play with so I will try to give updates when weather permits, i.e., What will increased aperture bring with the 15 second exposure limitation?

Dave Keller

I don't believe any damage in the form of chemical etching/reaction will occur on the optics or their coatings. The chemical used in mothballs is either Naphthalene or Paradichlorobenzene. These chemicals produce the odor through slow sublimation (conversion from solid to gas phase without forming a liquid during the change). They are relatively chemically inert so I don't see attack on optics as a problem. I believe all reflective and anti-reflective coatings are purely inorganic; mothball chemistry will not react with them.

There is a chance that a thin chemical deposit can form on the telescope via condensation. You should be able to tell if this happens by odor; does the scope smell like mothballs after being removed from the shed several hours later. I don't know if you will be able to visually detect any deposition. There is a chance that the mothball chemicals can affect some paints and plastics; maybe soften or dull a finish. Wood will definitely absorb the odor and may take a while to sublime back off. A shiny wood finish might dull from exposure.

I guess the best advise is "Maybe it's best to store the telescope away from mothballs to avoid the other potential problems".

Dave Keller