Supernova 2005ep article

Quite right Seanie! I guess I didn't really think to do that. I know the SN mag was given (17.9) in the official telegram and is quoted towards the end of the article.

Anyhow, UGC 10626 (AKA PGC 59288, AKA MCG10-24-77, AKA CGCG299-36) is a spiral galaxy of mag 15.9 - you'd need a pretty large aperture to see it visually, as well as very dark skies.

Here's a good definition and calculation you can use from Celestron:

"The faintest star you can see with a telescope (under excellent seeing conditions) is referred to as the limiting magnitude. The limiting magnitude is directly related to aperture, where larger apertures allow you to see fainter stars. A rough formula for calculating visual limiting magnitude is: 7.5 + 5 LOG (aperture in cm). For example, the limiting magnitude of an 8" aperture telescope is 14.0. (7.5 + 5 LOG 20.32 = 7.5 + (5x1.3) = 14.0). Atmospheric conditions and the visual acuity of the observer will often reduce limiting magnitude.

Photographic limiting magnitude is approximately two or more magnitudes fainter than visual limiting magnitude."

So my 8 incher should have only been able to make mag 16!

Cheers

Dave

Dave L - she's truly magnificent! As it happens, I just checked out the video from which the AP1200 was given its name from these boards. Truly magnificent too... :shock:

Cheers

Dave

Gosh Dave, I knew it was a big mount, but the 8" SCT looks like a beer can on it.!!! :shock:

And that's with the dewshield on... The C8 is actually shorter than the mounting plate it sits on :oops:

In spectroscopy, with all the supernovae that are discovered, most of the spectroscopy is done by the professionals. In spectroscopy, you don't need an optically accurate optics. Long exposures with a medium telescope would result in a spectra that can reach supernova mags.

From looking at supernova data for a project some time ago it seemed that there was a need for more accurate spectral analysis of the supernovae early on.

In recent years the amateur supernovae hunts have yielded a lot of information on the magnitudes of supernovae, which helps plot more accurate the early portions of their light curves. It seems however that spectral alanysis is still being left to the professionals, and there not enough with the capability to turn large spectroscopes onto target stars based on an initial report. Bear in mind that stellar spectroscopes are usually in the order of 2m telescopes.

Long exposures, big telescopes, and experience in getting and calibrating spectra would be required so perhaps its out of most Irish astronomers capabilities at the moment.

BTW I'm finishing up an article on amateur spectroscopy that the rest of us can manage to do! I've gotten some acceptable results with a 4" Mak and the 350D. More in a future Arcturus.

Cheers,
~Al

Albert,

I look forward to reading the spectroscopy article.

Regarding spectra of supernovae by amateurs, it is possible using medium size scopes 12 - 20 inches and applying "Rainbow" (200 line/mm grating in front of a CCD sensor to achieve 16 mag. Some of the key lines within the spectra would show up, but alot would be mushy which means that trying to differentiate detail regarding the 'types' of supernova would be difficult. Hence the use of a slit to refine those lines, but unfortunately the slit light reduces the chances again of ever reaching the neccessary mag.for potential suspernovae, of course the recent supernova in M 51 would be the exception at 13 mag. It may be possible by stacking images that an increase in mag threshold could be achieved to secure an improved resolution. This would take considerable time of 8 x 30 min exposures, certainly need a good mount for that one!

For your interest I designed and built a Cassegrain Spectrograph, but have not tried it on galaxies. If you are interested I have a published paper on it.

Eamonn A