Filters and Messier 33

[alan potts]

Let me start by saying I have always found Messier 33 a somewhat difficult object, everything has to be right even to see it well, I have known nights with the Moon up where I have just not seen it at all.

I have it pretty much overhead if you are not going to take it to the letter of the law, so should be about as good as you can get it, sky looks to have very good transparency with stars being visible right down to the mountain tops on my southern horizon though seeing was a bit poor but overhead taking X160 or so.

I was using the 41mm Panoptic in the 12 inch Meade which gives a power of X73, almost a joke to think that is a mid range power and is as low as I can go without  using a 55mm TV Plossl and that shows me no more in the way of FOV really and then only gets down to about X55 and when I had one prefered the Panoptic.

So I set the controls for the Pinwheel as I think it is called and when there checked it in the 70mm pigggyback scope which had a 24mm Panoptic on board giving a very low X17.5 and a 3.88 degree AFOV, enough for most things. I was fair supprised I could see Messier 33 in the centre of the low power field though it was no more than a fuzzy blur. Moving over to the main eyepiece I was very pleased with the view, feeling this was as good as I have ever seen it, put a smile on my face anyway. I then decided to try a Lumicon filter I had bought about 2 years before and never really used.

It was the Lumicon Deep Space Filter which is I believe the name they actually give their street light filter, not having any lights around as such I often wonder why I bought it. It was secondhand and about 100 pounds, so I guess it is a no lose purchase but sitting in a case keeping warm, a bit of a waste. I had read somewhere these filters work better from dark sites and are very good on galaxies, I am sure this was in one of the many threads we have had on the use of all types.

It is now I arrive at the point where I wish for Santa to give me a sliding draw to fit a filter or two into and slide away, leaving one draw empty for a clean view. There was no doubt in my mind that The Pinwheel was clearer and better defined with the fillter, switching back and forth about 20 times, being careful not to drop anything in the cold night air and the fact the observatory has a concrete floor, still, next job on the list.

I also tried the Astronomik's UHC filter as well but this didn't do anything for me at all on this target, I far preferred the clean view offered by the eyepiece only in this case, I knew UHC were better on the likes of M42, but it was worth a try.

The view offered by the Lumicon was a better than subtle improvement over no filter but I would not say run out and buy one only for this as they are very expensive for what they are. No doubt thought the spiral arms were discernable with direct vision and with averted I was able to tease out some extra detail, but I don't want anyone to think it was anything remotely like the photo's ones sees of this, it wasn't and I don't want people to think it jumped out at you it didn't, you had to work at it. I spent about 2 hours on the one target and would have spent longer. I think I may well be trying this filter on some other galaxies, maybe using Messier 31 as a target with the piggyback scope as the FOV will allow the whole of it to be in the field of view, though it's light grasp is much smaller than the carrier.

An interesting night cut short by our old enemy mister cloud.

Alan

[cotterless45]

M33 is just an absolute joy to observe, but from the darkest of sites. I got this on holiday and was just glued to the view !

It required no filters or averted vision. To see it just by eye is a treat. From those deep dark

Clear skies !

Nick.

[John]

Very interesting report Alan

It seems an age ago when I last observed M33 !

Though I don't generally use filters on galaxies I did find my DGM NBP filter made some of the "clumps" within M33 stand out a little more prominently where they contain H II regions of nebulosity. NGC 604 is the most obvious of these and can be seen clearly without a filter. Nicks sketch captures it.

If the skies here ever clear again , I'll try the NBP filter out on some other galaxies such as M101 and see what the results are. I don't currently have a broadband filter like the Lumicon DS because I tried a couple (not Lumicon) some while back and found little or no benefit for me.

I'm glad you have found a good use for the Lumicon DS filter though

[laudropb]

Very interesting tip Alan.I have only had decent views of M33 from very dark skies and under great seeing conditions. Will have to try some filters.

[estwing]

will have to investigate this....nice read Alan.