M104 The Sombrero Galaxy

While testing repairs to my scope, AND trying the new lightbox, I spent several hours last night gathering photons. Most will take time to process, but I wanted the toss this quick-and-dirty shot up here...it's M104, the Sombrero Galaxy, and note just above it, my first asteroid capture! While the stars are shaped more like potatoes than circles in all the subs, the dot in question showed no elongation in any one sub (about 25 overall.) So it traveled roughly 8' of arc in the period these subs were taken, roughly 30 minutes.

(I am still shooting 30 second exposures, but some are totally useless while the drive motor moves from one tooth to the next, and there is some time lost while each picture is written to the oh-so-slow compact flash card. It's a ten year old camera; it's not speedy. In an hour's shooting, I expect to get 40 exposures, ten of which I will toss out.)

There was some good news last night as well; that neighbor with the floods came out and yelled at her chihuahuas for a while around midnight-then shut the lights off! I was even able to see this galaxy visually, if only just; it's been many years since that was possible.

This image will only improve with some additional subs and some more careful post-processing; I only had time for roughly 25 usable subs. The next time I can shoot it, I plan on trying to enlarge the view. So far, I have been only using prime focus camera placement, which puts the camera right in the focusing tube. This gives the image about 20x magnification. That is not much, but this sort of scope is not intended for high magnification-it's simply a light bucket for wide-field views. Positive Projection placement puts the camera "downstream" enough to allow the insertion of magnifying eyepieces. It's much trickier getting everything aligned well, and the extra glass is a source of distortion. Also, a magnified image will be dimmer-the same number of photons will be spread over a larger section of the CMOS "film". But, at an apparent diameter of about 8 arcminutes (the full Moon is about 30 arcminutes accross) this galaxy only takes up a tiny part of the field of view-in fact, only about 300 pixels. A full frame at prime focus is about 45 x 60 arcminutes (60 arcminutes =1 degree.) I think that if i can get a solid setup with 100x magnification, I should be able to get the longer exposure needed, and that would make the target cover well over 1000 pixels.

The Sombrero Galaxy is one of the most beautiful in the sky, and one of the most stunning photos from the Spitzer space telescope is of M104, in infrared. It's almost impossible to believe it's a real object, but it's utterly mind-bending. Here is a link to it. What look like dark cold clouds of dust visually are actually hotbeds of star formation, and they create the incredibly well-defined ring around the galaxy. Worth looking at, even though it certainly will make my efforts look pretty silly!

As for those potatoes...Partly, that is due to stacking more of my subs than I normally would, since I had very few. So there were some frames that i would usually toss out. Focus is also a component; the tempurature seemed to have dropped during the 20 minutes between focusing and starting the exposures (during which reference frames are being taken.) To some degree, collimation is also to blame, although it is-so far-as good as I can get the repaired scope to perform. I need to do more work on the secondary mirror spider especially, and I think the mirror holder itself has a lot of room for improving the original design. (Mind, those spud-shaped stars were much worse when I started back in January.)

In this shot of my scope, the flat black areas show the section that was dented; the black is primer over the bits of exposed metal left after rolling the metal in the tube. The focuser was stove into the main tube at roughly 30 degrees, while the spotter scope mount was bent to the side about the same amount. The only unrecoverable part was the spotter scope holder. It just turned into a chance to learn more about the construction and subtleties of setup; I think with even a little more work it should be better than before. And I suppose it helped having been a brass instrument repairman...that at least saved the cost of a new tube, and all the parts to adapt my optics to it since this tube is between the sizes offered by all the DIY scope-building suppliers.

I'm trying to get in the habit of shooting a quick snapshot of the camera and scope with each session, so that future sets of the same target can be shot with the same camera angle. As a side note, you can see there has been some rain this winter, for a change...there is some water damage to the house to repair once everything dries out. (One of the rainy days a couple of weeks back, we received over 6" in a day! It's been cloudy ever since; I was happy for the humid lousy seeing last night, because it was at least clear.)

Today or tomorrow I should be able to post some pictures showing why the lightbox was worth the effort, with another picture of the Leo Triplets, M65, M66 and NGC 3628. The improvement is not incremental; it's a giant leap forward.