Unknown Nebulosity

higginsdj · #1 14-05-2007, 09:33 AM

Hi all,

I was busy sleeping whilst my observatory was taking photometric data for MP 28736. On viewing my images I thought "wasted night" as 1/3 of the frame was void of any stars - I assumed cloud or dew. Problem was my observatory was taking data for 2 other MP's and there was no cloud and no dew evident on those fields.

Well I did a track and stack of all 44 x 4 minute images and sure enough - its a dust cloud or nebulosity of some sort. Can anyone identify it please? Image is centered on 15 54 22.56 -02 49 24.16. My target was the dotted line.

Cheers

higginsdj · #2 14-05-2007, 10:15 AM

I think it might be the edge of either LDN 188 (434) or LDN 175 (431). DSS images don't show much except a void.

Cheers

avandonk · #3 14-05-2007, 10:27 AM

Here is a map generated with Star Atlas Pro centered on your coordinates. Looks like it could be LBN 19

Bert

higginsdj · #4 14-05-2007, 12:21 PM

Thanks Bert, Guide 8 does show LBN 19 but much smaller in size.

Dr Nick (Nick) · #5 14-05-2007, 05:08 PM

I've come across these unexpected objects too, it seems, the one I found was the flame nebula...

higginsdj · #6 14-05-2007, 11:23 PM

This ones a bit fainter Nick, the brightest part of the cloud is registering pixels at magnitude 20 - very close to what one might consider the background sky limit (though that mag 20 limit might be a stretch since it, Astrometrica, also registered my asteroid at magnitude 18.8 even though it really was 16.0).

I guess it just goes to show you can only stack so far :-)

Cheers

David

jase (Jason) · #7 14-05-2007, 11:58 PM

David, I'm not sure what astro CCD control software you use, but I'm assuming you write out your astrometry data in FITS format. Depending on the software you use, you can modify the FITS header info to also include RA and DEC of the centre of each image. I know MaximDL supports this feature, so would expect others do too. You can then use this information to determine the precise pointing location. As you're aware, if you make a discovery this information is critical. You can also time stamp the exposure based on UTC or Local.

More info on the FITS headers can be located at http://heasarc.gsfc.nasa.gov/docs/he...wg_recomm.html

higginsdj · #8 15-05-2007, 12:44 PM

Thanks Jase,

MaxIm and ACP autosolve and stamp my images while Astrometrica takes care of the track and stack duties as well as the subsequent measurements.

Cheers