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A very crisp and cold night. I added more luminance data and also collected some RGB for NGC 2841. There is now around 4 hours in L and an hour each in R, G and B. The subs are 114s at a gain of 139.
NGC 2841 is an unbarred spiral galaxy in the northern circumpolar constellation of Ursa Major. A 2001 Hubble Space Telescope survey of the galaxy's Cepheid variables determined its distance to be approximately 14.1 megaparsecs or 46 million light-years.
This is the prototype for the flocculent spiral galaxy, a type of spiral galaxy whose arms are patchy and discontinuous. The morphological class is SAa, indicating a spiral galaxy with no central bar and very tightly-wound arms. There is no grand design structure visible in the optical band, although some inner spiral arms can be seen in the near infrared.
The properties of NGC 2841 are similar to those of the Andromeda Galaxy. It is home to a large population of young blue stars, and a few H II regions. The luminosity of the galaxy is 2×1010 M☉ and it has a combined mass of 7×1010 M☉. Its disk of stars can be traced out to a radius of around 228 kly (70 kpc). This disk begins to warp at a radius of around 98 kly (30 kpc), suggesting the perturbing effect of in-falling matter from the surrounding medium.
The rotational behaviour of the galaxy suggests there is a massive nuclear bulge, with a low-ionization nuclear emission-line region at the core; a type of region that is characterized by spectral line emission from weakly ionized atoms. A prominent molecular ring is orbiting at a radius of 7–20 kly (2–6 kpc), which is providing a star-forming region of gas and dust. The nucleus appears decoupled and there is a counter-rotating element of stars and gas in the outer parts of the nucleus, suggesting a recent interaction with a smaller galaxy.
Equipment: Celestron 9.25 XLT at F10, Skywatcher EQ6 Pro GEM, ZWO 1600MM Pro, ZWO EFW with ZWO LRGB filters, QHY5IIC guide camera on Skywatcher 9 x 50 finderscope
I recently spent my Xmas money on an L-Enhance filter as I have seen amazing results with this filter.
I took it for a test run on the Y Cas Nebula last night (not the best night, but when is?)
I managed to get around 43 mins of time.
I normally shoot 1 min exposures with my 1000D modified camera but I thought I'd go for 90 seconds as the filter would reduce brightness? (any thoughts on exposure times here would be great)
The results were not as great as I was hoping for - see below.
O over stretched it just to see if I had captured the 'ghost'. He's there, but it turns out really grainy and not the nice subtle wispy nebula that I see from other folks.
So my questions are:
- is this a tricky nebula target?
- What exposure times should I run?
- Is 43 mins way too little for this (or any) target?
- any other advice???
Canon 1000D - modified
Skywatcher 72ED Telescope
Skywatcher AzGTI mount (AZ mode at the moment until I can get polar alignment working with SharpCap)
Any thoughts, hints, tips greatly appreciated!
Thanks in advance!
By Anonymous Astronomer
I'm looking to buy some NB filters and wanna make the best decision.
1. Does the size of the filter impacts the quality of the image? (is it a big impact?)
2. I know that lower HBW is best, but... for example: does the difference between 35nm and 7nm is worth the price?
3.Can you recommend some H-alpha, OIII, SII?
Thank you in advance!