Tomorrow night is Messier Marathon night and it looks like it may actually be clear!
Considering what we often see for the MM, this will be relatively balmy (wind chills in the teens
above zero) and dry (the observing field is a little mushy, but there's no snow). It helps that this year it's being held in April even if that's not best for getting a high count.
Having gone over to the imaging side, that's what I'll be doing. To keep in the spirit of things I'll do mostly Messier objects.
Because the Ms are fairly bright I'll be using my DSLR. The targets will be taken from the two Astronomical League lists I'm working on, Arp galaxies and planetary nebulae.
Here's the list, Galaxies first:
These all have surface brightness between magnitude 21.3 and 22.3, so I think they can be imaged fairly quickly for modest quality results; it
is a marathon night. Because M65/M66 occupy the same field of a TV-102 and DSLR, they require only one image. So for the six galaxies I'm expecting four to five hours of clock time including time for acquisition, composition and dark frames.
Next the planetaries and their surface brightnesses:
- M97 (22.3)
- Abell 21 (24.9)
- Abell 36 (25.5)
- Abell 35 (26.2)
- PN G164.8+31.1 (26.6)
You can see why the last four are not Messier objects; they're not very easy to see. Abell 21 is about three times larger than M97, making it a good target for the relatively short focal length TV-102 (700mm). Given its location in Gemini it might be the evening's first object and will get up to two hours of photons. The other dimmer objects will probably get passed over.
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