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Skyheerlen
December 20th, 2022, 08:54 AM
I've used the Uranometria 2000.0 for year; happy with it. Until recently: I 'discovered' the IDSA. Main differences: the Uranometria shows many many very faint galaxies (ideal for mij 30" telescope), and the IDSA shows much more large/faint (dark) nebula (ideal for my 13" at La Palma).

Last month at La Palma was the first time I really used the IDSA in a very dark area. There were a lot of new objects to dicsover I never know before: LDNs, Sh2's (many of with are not shown in the Uranometria).

But ...

During the seven full nights observing at La Palma, I've seen many more bright (not so bright!) and dark nebula, that are not shown in the IDSA. And now the problems starts: how to identify these nebula? I also do use SkySafari, but in most cases, it only shows squares at the approx. location of those nebula. So far, I was not able to find an atlas that shows more LDN/LBN nebula (and even ICs) than the IDSA. What is the next step? Who knows a better atlas for these objects?

RedshiftRob
December 21st, 2022, 01:28 AM
I've been looking for a new atlas somewhere in between the S&T PSA and URA for my 16"f4.5 and this sounds like a good option. I always been weary about using URA out at the scope because it's very wet (dew) here in the US-PNW for a good portion of the year and I don't want to get it soggy. Plus there are alot of things in there that I probably won't be able to see except under the darkest skies. Going to take a closer look at this one.

Thanks!

-Stephen

Don Pensack
December 24th, 2022, 02:37 PM
You need a Nexus DSC Pro Digital Setting Circles device.
It's not an atlas, but it contains the following catalogs with detailed information about every object:
https://www.astrodevices.com/resources/Nexus-DSC-Pro/Nexus-DSC-Pro---List-of-Catalogues-1.1.5.pdf

I think Uranometria 2000.0 is about ideal for a 12.5" scope under dark skies. But, even then, I can't tell you how many times I've seen one galaxy at a spot on the page and seen 3 or 4 galaxies around it, in the scope, that are not listed.
I look up the field at home in a computer atlas and see there were actually 20-30 galaxies there. Which ones did I see?
Selection of objects in U2000 seems to vary. Some objects are not seen in my aperture, while others are seen with companions not listed. The perils of making an atlas is the availability of data that really describes the visibility of an object,
not just its magnitude (which is often wrong when reaching V magnitudes of 15 or deeper, and often not related to its appearance in the scope).

Still, I don't think a printed atlas will ever go as deep as a 13" scope can go in truly dark skies with an experienced observer, especially in galaxy groups.
For those plumbing the depths, printing a chart of the area from a computer atlas is just about the only way to identify all the small faint galaxies visible.
You wouldn't use an atlas that had that scale, anyway, as it would be thousands of pages long.

One complaint I have about the IDSA is its binning of objects into scope sizes in which they're visible. First, I disagree with a lot of the binning, and second, that is a subjective evaluation
that shouldn't be in an atlas of the sky. Subjectively, I would also have preferred to see some margins at the edges of the pages, but the scale is good. It is quite usable in your lap.

eyeoftexas
December 25th, 2022, 01:55 PM
Has anyone tried using the (out of print) Great Atlas of the Sky, Jubilee Edition? That has far more DSO’s that either.

I haven’t tried the Nexus as an identifier at the eyepiece. I’ve assumed it is only as good as your alignment, and mine rarely are that spot on.

Don Pensack
December 25th, 2022, 04:05 PM
You're right about the Nexus used as an identifier, but, then, the same would be true of Sky Safari as well.
Both would do fine to identify a bright object, but not identify a galaxy in a crowded field.
Most star atlases would not be useful then, either.
Only a screen shot from a computer atlas would suffice.

wvreeven
December 25th, 2022, 09:12 PM
SkySafari has a LOT of deepsky object but I don't like using it at the eye piece for two, for me ver important, reasons:

- the binning of the stars is exactly wrong meaning that stars that are close in brightness are drawn as very distinct symbols, suggesting that one is MUCH fainter than the other, and stars that differer a lot in brightness are drawn as equal symbols, suggesting that they are of similar brightness
- groups and clusters of galaxies are missing, despite my request to draw them with distinct symbols many years ago

Especially the first makes me not want to use SkySafari while observing. In that respect SkyTools works much better for me.