LSR0602+3910 - Brown Dwarf in Auriga

Gents,

I am delighted you found the brown dwarf of interest!

Eamonn, my use of the other filters had a dual purpose. First, I wanted to produce a "normal" star field (ie. RGB) which would be suitable for presentation along with the brown dwarf as opposed to just a monochrome image (probably inverted) showcasing the dwarf. Secondly, I was interested to see how dim, if present at all, the dwarf would be in the other channels.

In relation to your other question surrounding exposures, my philosophy is to pursue the longest possible exposure (ie. sub) which my skies allows. Yes, it is better to have many short exposures for stacking so as to maximize the S/N ratio but I prefer to sacrifice some "S/N" for greater signal and especially when dealing with such a challenging subject as a brown dwarf.

Your question brings to light (excuse the pun) the dilemma we always face ... do we pursue fewer but longer exposures so as to have depth or do we pursue many but shorter exposures so that we maximize our S/N and have a nice clean background. Whenever possible I try and find something in between and, in the case of the dwarf, I really did not have a choice but to pursue 'depth' as opposed to a maximized S/N.

I have observed that I get a very good S/N when my NUMBER of exposures is at least six and especially at least nine. To this end, I will often investigate if I can have the best of both worlds keeping in mind my general observation surrounding the six or nine sub minimum while maintaining a desired exposure length.

I hope all of the above makes sense.

Phoenix,

I use a limiting magnitude scripted programme within the software engine DC3 ACP 4.2. It is trial and error. However, you can arrange the sequence of exposures that suits your instrument, tracking capability, CCD performance. In my case, I use exposures of 30 secs, 75 secs, 188 secs, 472 secs. This latter exposure time sequence may not suit all scopes. This could follow from the 188 secs as 240 secs, 300 secs and may be 472 secs.

See www.astroshack.net/eamonn.php for more details

Eamonn A

Another first Anthony and many congrats, expect to see this in the magazines before long.

I admire the dedication you put into your art and how waiting for that perfect moment pays off.

Can't wait for the next first.

That really is a stunning piece of work Anthony - mag 20.88 - wow! :shock:

With a visual magnitude of 20.88

Anthony - any idea what the IR magnitude is? Or can you convert the I mag with your Baader IR Pass?

I'd be surprised if even an AP refractror can get down to mag 20.88 :shock:

Then again, Roland know his stuff...

With a visual magnitude of 20.88

Anthony - any idea what the IR magnitude is? Or can you convert the I mag with your Baader IR Pass?

Hi Dave,

I wish I knew how to convert the results of the Baader IR Pass but I have no idea. The only reason I used it is due to the fact that a lot of brown dwarfs have their strongest signal in the IR portion of the spectrum whereas they are very dim in the visible portion. Personally I was quite apprehensive since my ST-2000XM has a very weak response in the red and I did not know if this lack of response would do me in or not.

I remember one time during the summer I took one of my images (I think it was M27) and I started playing around with the dimmest stars I had captured after calibrating for the magnitudes of existing known stars. I was getting results which suggested at least 18th magnitude.

Within AIP there is something called instrument instrinsic magnitude and I can get results up to 25th magnitude. Now that I remember, it was on this occasion that I calibrated and pursued the dim stars in my image of M27.

I'd be surprised if even an AP refractror can get down to mag 20.88 :shock:

Then again, Roland know his stuff...

I suspect it is more of an issue with the CCD camera and stacking enough exposures to get a really good S/N. Of course, a 6.3" APO does have its limits as well but then nothing seems to be out of reach for these wonderful instruments.

I remember a few years ago reading a passing comment in S&T about an amateur who reached mag 23 (a first at the time) with "average" equipment (I am going by shear memory).