Posts Made By: Greg Bradley

Here's a shot of the Keyhole Nebula. RCOS 12.5 inch (318mm) with AP .75 telecompressor for F6.75. Unguided on a Tak NJP mount that was really humming along beautifully.

Modified Nikon D70, Images Plus acquisition and stacking, Nikon Capture Editor for processing.

4 x 3 minutes unguided. I was getting up to 5 minutes unguided last night with a 2130 odd focal length - amazing. Shows the value of putting in the time on a good drift alignment.

The main yellow star there is Eta Carina, one of the most massive stars known to man. It blew a lot of its mass and that formed the nebula. It is an unstable star and could supernova.


Greg.

I took this shot from my backyard about 3 weeks ago during an all-nighter (the 3rd of 3 in a row - yawn!).

RCOS 12.5 inch, Tak NJP mount, modded Nikon D70, 3 minute unguided shots after spending some time drift aligning (45 minutes or so).

I kind of cheated on the drift alignment in that I went only to one star - Canopus, very high in the sky and used it for both alignments.

The RCOS is a sweet scope and gives great visual images that are not far from refractor sharpness. Its a bit of a beast to set up and break down each night though so it needs to be more permanently mounted.

Greg.

I am deciding which camera to get.

After viewing various images I am not sure if the modded 20D is worth the extra dollars over the modded 350D.

Can someone steer me here?

One factor is I can get a new 350D fairly cheaply and modify it myself and take the risk of damaging it. I'd spend the saving on the remote control and filters. But a new 20D costs too much for that risk so I would buy one already modified.

20Da is nice but rather expensive for basically live preview (I use a laptop anyway) and perhaps less sensitivity than a modded camera but slightly lower noise which could be handled by cooling the camera.

Greg.

I am interested in buying a modified 350D. If anyone has one, please let me know.

Greg.

Here is the Tarantula Nebula.

Sbig 2000XM HaRGB 5 each about 90 seconds.

William Optics 80mm fluorite triplet, NJP mount.

Greg.

I heard the Astronomik UHC filter lets through Halpha,O111 and H beta all in one. So I thought I would give it a go.

Sbig 2000XM, William Optics 80/480 triplet, TV.8X flattener/reducer, NJP mount, CCDSoft, Images Plus.

3 x 5 minutes at 24C (desiccant needs replacing, frosting occured as soon as I cooled it, surprisingly little noise though).

The main point here - it was a full moon! And from my backyard, so I am very happy with that.

Looking forward to doing that again at a dark site and also shooting some colour.

Greg.

I have been imaging the Horsehead and using a Schuler 10nm H alpha filter, William Optics fluorite triplet 80/480 with TV .8X reducer/flattener, Sbig 2000XM at -10C, Tak NJP mount.

3 x 15 minutes. When I get a few more clear nights I'll take a bit more, maybe 30 minute exposures, some UHC filtered images and luminance and colour shots.

Greg.

Hi,

I just had a look at the new Canon 30D at a local camera shop here in Sydney.

Very nice.

I had the guy do a 5 minute dark exposure at ISO 1600 with the shop at about 24 degrees C. I could not see any noise at all on the lasrge 2.5 inch LCD screen. But that may be the same for the 20D as the imaging system is the same.

The camera also has a sensor cleaning function in the menu. I am not sure what that does and if the 20D has that also.

The automatic noise reduction system is of great interest to me. It is the same as the 5D where the camera determines whether to apply noise reduction if needed and it also does not make you wait to take another exposure whilst it applies noise reduction.

It certainly looks good and feel good. A very high quality camera.

Greg.

Here is a shot of my roll off roof observatory which is a converted garden tool shed.

Imaging setup is RCOS 12.5 inch, Tak NJP on an Mountain Instruments MI8 pier and an SBig 2000XM and a Dell P4 laptop. Tracking autoguiding errors are well under 1 pixel and sometimes I get it down to about .2 or less. Not 100% polar aligned either.

So the NJP is sweet indeed.

I've imaged a number of objects over the last few weeks where we've had a few very clear nights finally. Once I master the processing I'll post one or two.

Greg.

Can some of the more experienced CCD imagers let me know what their general image work flow looks like? Also how they save their files etc.

A few things have become obvious when handling lots of exposures using CCDs. One is the number of files and the number of new files created to handle the aligned files etc etc. The need to keep a log of what you took, how long, what temp, what colour, what binning was used.

It seems it goes something like this:

0. Create a library of dakrs for both 1 x 1 binning and 2 x 2 binning at the temperatures you will be imaging at. Take 3-5 darks and median combine the results to create a master dark and label it carefully and all darks under a master file of "Darks 1 x 1 binning" or "Darks 2x 2 binning".

Take a flat by exposing the telescope at dawn or dusk skies away from the sun at a uniformly lit part of the sky for long enough for the average pixel value to be arund 30,000. Use the clear filter.

1.Take exposures and make sure you have autosave on and the file you want the images to be saved carefully labelled with object name, colour of the image, exposure time, binning, temperature. Right here there is a problem as CCDSoft only records the colour and no other data if you do a colour run. Does add the temp, exposure length or binning (or can it be made to do that?). So I have started to label the files from a colour run like this: M20,L30 1x1 R15 G7.5 B15 2x2 -20C. each file gets that label and CCDSOft will put the colour at the end of each file as well.

2.Align the entire folder of images.

Again here is another problem. The common practice of luminance at 1 x1 binning and colour at 2x2 binning makes it so CCDSoft sometimes will align 1 x 1 and 2x2 and other times it will not (I think if they have been processed in any way it does not seem to want to do it). Now that means I have to resize the 1 x 1 images which seems to be another unnecessary step.

3. Dark subtract each image and then process them for background and brighten/contrast using CCDSoft. If you took a flat then divide the resulting image by the flat at this point.

Then save to each LRGB separate file for later combining of multiple individual colour shots. I also have been doing repair for cold and hot pixels, Hard to notice the difference but perhaps that shows up later.

4. Combine the several sub-exposures for each individual LRGB or Halpha and save.

5. Open these resulting combined images for LRGB and do a colour combine using CCDSoft and play with the colour balance so it looks OK. I have found in my limited expereience so far that CCDSoft does not do such a great job at this. Now it could be my images for RGB are not at the ideal exposure length but I have been advised for an SBig 2000XM it is R 1 G.5 B1
as a ratio and Luminance from seeing lots of images seems to be 2 - 4 times the length of the longest colour image.

Perhaps Photoshop CS2 would be better for the colour combine as it has layer technology. Comments here?

6. Now you transfer the image as a Tiff file to you image processing software for colour balance, noise reduction, curves etc etc.

Does that sounds about right?

The labelling and creation of new files to save processed files at different steps needs to be standardised for me so it reduces confusion and time in processing. Not remembering 100% what the exposure lengths were after the fact means you could subtract the wrong dark.

Also is there any freeware for an imaging log to record this for referral to afterwards when processing the images. I see sometimes people reprocess images rom several years earlier so that becomes an even more vital step to do.

Greg.