M13 in 1 second exposure

[nytecam]

A great if brief session last night on ~10 DSOs included M57, M13, M92 in southeast then north of zenith into Draco with Catseye PN NGC 6543, a 'nearby' quasar and some faint and distant galaxy groups - very satisfying

Here's quick and dirty M13 in just 1 second exposure recording down to mag14 and same exp on Catseye - no darks or flats - see sig for gear. It's amazing how brief an exposure goes so deep

[Gina]

Amazing!

[nightvision]

I find this short exposure approach really fascinating. I gather you did this at F3.7 with the SXV-M9, is that correct? If so do you have any idea how much longer exposure would be required (to get similar results) if you used your 300D DSLR?

I am interested as I have just completed building some very fast scopes from my large bits box, I constructed a 100mm F4.2 achro, a 100mm F2.8 achro and a modified 100mm F9 Apo operating at F3.5. Initially I intend to use them with my modified 1000d.

[nytecam]

Hi Gina & Tony - thanks for your interest - did suspect my thread title wouldn't go down well on a forum renowned for exposures in hours rather than seconds

I find this short exposure approach really fascinating. I gather you did this at F3.7 with the SXV-M9, is that correct? If so do you have any idea how much longer exposure would be required (to get similar results) if you used your 300D DSLR?

I am interested as I have just completed building some very fast scopes from my large bits box, I constructed a 100mm F4.2 achro, a 100mm F2.8 achro and a modified 100mm F9 Apo operating at F3.5. Initially I intend to use them with my modified 1000d.

Tony my SXV-M9 DSOs via Meade f/5 ETX-70 @ http://home.freeuk.c.../etx70mg_gx.htm with video compilation @

which had exposures running into many minutes and were not very sharp [iR 'blur'] but I've moved on since. Currently using 30cm f/10 SCT @ a blazingly fast f/3.7 + unfiltered OSC Starlight Xpress Lodestar-C which has dramatically reduced exposure times by at least an order of magnitude

The ETX-70 aperture was little larger then the central obstruction of my SCT. It's aperture than records stars and fast f/ratio extended objects like DSOs in brief exposures that I use. Never had much luck with D300 on DSOs - my Lodestar-C software has a near magic 'light pollution' filter that removes my horrid orange skies [i've 7m 'neighbours' in London] to a neutral grey Good luck in your quest

[Cloudwatcher]

Great stuff...........do like single exposure images.

[Pete Presland]

excellent images, especially like the cats eye amazing for a 1 sec exposure!

[Andy_E]

Tony, out of interest I was wondering the same thing a few weeks back. tired of 'stacking and tracking', I had a go at m13 with a 6" dob attatched straight to a canon 40d. at ISO3200 I could JUST about get away with around a 3sec exposure... but it was as noisy as hell! I'll dig the image out and post it if you're interested.

Andy

[nightvision]

Tony, out of interest I was wondering the same thing a few weeks back. tired of 'stacking and tracking', I had a go at m13 with a 6" dob attatched straight to a canon 40d. at ISO3200 I could JUST about get away with around a 3sec exposure... but it was as noisy as hell! I'll dig the image out and post it if you're interested.

Andy

Yes interested, what is the F# of the 6" dob? You say tracking, does the dob track? (my dob just nudges and jerks about, good enough for visual)

Surprised you got noise at 3 seconds! (ahh just noticed... ISO3200 probably accounts for the noise)

[nytecam]

Here's M92 GC Her again in 1 second exp

, 2x30s ave [centre] and M57 20s

- same set-up as M13 above

[Andy_E]

It's an f8 (really bad for short exposures!). Probably should have mentioned, my normal photography setup is a 400mm lens on a tracking mount. I was just intrigued what would happen (3 seconds on a shot seemed quite attractive as opposed to the usual 40+ 1 min exposures!). turns out it's nowhere near as good as these images... I must say they're stunners for short exposures. I've seen plenty of 'track'n'stack' images that aren't as good as these!

Anyhow, here's m13 at 1200mm f8 3sec exposure and ISO3200. To be honest I was going to bin it as a failed experiment, but in the name of sharing...

ps; the granulation in the core is processed noise not detail!

[nightvision]

Some of that must be information as it looks like a globular, seems to me that 30 of those would deliver something worthwhile. So its no surprise that a very sensitive camera and a fast scope will deliver quickly. I was thinking that if you have a typically large DSLR chip (compared to expensive small sensitive dedicated CCDs) you can get considerable magnification from cropping (to compensate for the smaller image size resulting from low F#) without too much loss off detail. Just about to build an obsy so no imaging/experimenting for a while.