M104 Sombrero Galaxy

[2020BC (Bill Christie)]

Subject: M104 Sombrero Galaxy (NGC 4594)
Camera: Canon 350D (unmodified) prime-focus in an 8" Meade LXD-75 Schmidt Newtonian (Focal length=812mm)
Exposure: Unguided 40 x 30secs ASA1600 Noise Reduction On.
Processing: Aligned and stacked in MaxDSLR. Processed in ImageReady.

[Starcrazzy]

awesome...what a nice image. well done...the 350 goes good don't it...

[acropolite (Phil)]

Nice image Bill...is Canon is good...

[RB (Andrew)]

Oh yeah,

Very nice indeed, well done BC.

[tornado33]

Yep, nicely done there.
Scott

[JohnH]

Originally Posted by 2020BC

Subject: M104 Sombrero Galaxy (NGC 4594)
Camera: Canon 350D (unmodified) prime-focus in an 8" Meade LXD-75 Schmidt Newtonian (Focal length=812mm)
Exposure: Unguided 40 x 30secs ASA1600 Noise Reduction On.
Processing: Aligned and stacked in MaxDSLR. Processed in ImageReady.

ASA hmm, showing a little vintage there I suspect .

Very good shot - I have only had a go at M49 so far and have nothing I would care to post...shooting faint fuzzies is something I aspire too, I am on the bright ones only so far. I assume this is a crop at full res?

One thing (wee actually one of the many things) I have not figured out is locating and framing the dimmer objects, how do you do that? Do you locate visually and then switch to the camera? With my setup I cannot use the FR and flip mirror at the same time and I think imaging at 1800mm is beyond me at the moment...

[2020BC (Bill Christie)]

For M104 I do similar to the following:

1. Rough align by placing tripod feet into usual circles (black texta-color marks) on driveway concrete;
2. Balance scope - optimise for direction of M104;
3. Use Mintron video camera fed to a TV for polar alignment (I only ever need a small horizontal adjustment); Ensure no/little DEC drift over 3 mins.
4. Load the Canon 350D camera and connect video cable to TV.
5. Get focus exact using a Hartmann mask and a bright nebula;
6. Do a rough two-star Goto Alignment (LXD-75 mount) via Telrad/finder;
7. Test Goto accuracy on some bright targets;
8. Goto M104;
9. Take 15-20 second exposure;
10. If M104 is visible in the photo when reviewed on the TV then centre it by comparing the location of brightest stars on the TV with the ones visible through the cameras optical viewfinder (this is easy);
11. If M104 is not visible assume it is easily within 2 degrees of where you're currently pointing (Goto won't be that far off) so use your Telrad to take 20 second exposures one degree up, down, right and left of centre. The field of view of the Canon 350D camera in an LXD-75 SN-8 (focal length 812mm) is about 1.6 degrees so it doesn't take long to find what you're looking for. M104 is very bright and you will definitely see it like a large bright streak on the image when you nail it;
12. Centre M104 as per step 10;
13. Take 50 exposures (ASA1600, 30 secs). Align and stack the best of them (the ones with no star trails) in software (eg. MaxDSLR or similar).
14. Do a Log stretch;
15. Histogram the black points on Red, Green and Blue;
16. Histogram the white and mid-point to taste;
17. Create a Luminance layer from Red, Green, Green converted to Mono;
18. Histogram to taste;
19. Apply noise reduction/blur technique - unsharp mask, blur or some such (also consider Noiseware);
20. Sharpen slightly (very slighty);

Hope this helps.

[JohnH]

That is exactly what I was looking for - thank you for sharing. I have not been able to make it to any observing sessions or star parties - yet. Life keeps getting in the way (family guy !). Working this stuff out the hard way under the stars wastes valuable photon trapping time so I really appreciate being able to pick peoples brainds this way. Thanks again.