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Star Atlas for Q-3.5

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#1 JimK

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Posted 30 July 2012 - 04:49 PM

Last night I was looking for carbon stars, before clouds rolled in, and was using Sky & Telescope's "Pocket Sky Atlas" (PSA) -- which goes to magnitude 7.6 stars. When I got to "T Lyr" I got lost a little.

The Questar finder is very low magnification (4-6x) with a small aperture (~15mm), so that when Luna is in the sky the fainter stars in the PSA are not seen. Then when switching to the telescope mode, many many stars that are not plotted in the PSA become visible, and the true field of view is, at best, only about a degree of sky. So in using the PSA last night with Luna up, I got a little lost. (And the clouds moved in.)

I am thinking that T. Taki's "8.5 Magnitude Star Atlas" (available for free, at this link) will work better. I printed it on 8.5x11-inch paper, thus it is physically smaller than Sky & Telescope's "Sky Atlas 2000" yet it shows fainter stars than the PSA. I glanced at the chart for "T Lyr" and it seems it may work for me.

Another option is J.R. Torres' "TriAtlas A-Set" (also available for free, at this link), but the labels are very small for my eyes unless I print it on 11x17-inch paper. However, the 11x17 size is just as unwieldy as the Sky Atlas 2000 in the field with a Questar.

I don't know of a PSA-sized atlas that plots stars as faint as magnitude 8.5 (thus I'll try Taki's), so what do you use for a star atlas when using a Questar 3.5-inch?

#2 dib2

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Posted 01 August 2012 - 02:41 PM

Greetings JimK,
On my Quantum 4, I use a green laser nested against the finder to zero in to the approximate area, then I use the finder. My 4's finder is small, too, but not 15 mm.

To START with,it seems that an atlas with, say 5th magnitude max, would help too, since that shows fewer stars, not more, which is what you're experiencing with a small finder.

Best,
dib2

#3 ColoHank

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Posted 01 August 2012 - 07:14 PM

Use the Q's excellent setting circles! Any atlas that lists celestial coordinates or has maps from which the coordinates can be extrapolated will suffice if the scope is properly aligned. Better yet is any planetarium application which allows the user to set limits of magnitude to suit personal preference.

#4 JimK

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Posted 01 August 2012 - 10:20 PM

On my Quantum 4, I use a green laser nested against the finder to zero in to the approximate area, then I use the finder. ...

To START with,it seems that an atlas with, say 5th magnitude max, would help too, ...

Thanks -- I got to the right general area, but I couldn't use the Pocket Sky Atlas (PSA) to star-hop to T Lyr because I got lost in the star field when in telescope mode. So a green laser (which I have used with the Questar in the past) would not have helped.

The PSA, chart 63, shows a few stars (including T Lyr) between Vega and Kappa Lyr. In the finder I could only see Vega and Kappa, thus initially I could only get to the general area. However, in Taki's "8.5 Magnitude Star Atlas", chart 19 shows over a dozen stars in the same region. On the next night I *was* able to find the intensely red T Lyr based on the matching the Taki-plotted stars to the stars visible in telescope mode. So it seems that the solution to *my* need may be Taki's star atlas.

#5 JimK

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Posted 01 August 2012 - 10:25 PM

Use the Q's excellent setting circles! ...

Better yet is any planetarium application which allows the user to set limits of magnitude to suit personal preference.

Actually, I prefer to star hop without bothering to do more than point the Questar's polar axis to the general area of "north." And the setting circles are really not accurate enough for locating a particular faint object.

I really do *not* wish to take a "computer" planetarium to view with a Questar -- for me it is too much baggage and destroys the experience.

I have found that Taki's "8.5 Magnitude Star Atlas" worked well, for *me*.

#6 JimK

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Posted 01 August 2012 - 10:26 PM

I have now found that, for me, Taki's "8.5 Magnitude Star Atlas" works.

... so what do you use for a star atlas when using a Questar 3.5-inch?


or do most people limit themselves to being a SLAP (solar, lunar, and planetary) observer.

#7 justfred

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Posted 03 August 2012 - 10:48 PM

Jim,
Thanks for the info on the star charts. I especially liked the Taki Atlas. I have been using the Pocket Sky Atlas as well but will look at the Taki charts as a serious alternative.
I'm in the Colonel's corner on the setting circle use. I enjoy star hopping with my dob but must admit that the setting circles get a pretty good work out during each session with the Q.
Thanks again for sharing the Taki Atlas with us.

Fred

#8 JimK

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Posted 21 August 2012 - 01:49 PM

Can anyone else find carbon star T Lyr (18h32m, +37d) using their Questar? It is high in the sky for many northern observers.

Use the Q's excellent setting circles! ...

... I'm in the Colonel's corner on the setting circle use. ...


As a result of these comments, last night I finally located T Lyr using the Q's setting circles -- I had located T Lyr by star-hopping with the Taki Atlas back in late July, but since then I have had weeks of cloudy nights. For alignment (after setting the Questar towards North) I used a cross-hair eyepiece, Polaris, and Antares (in Sco) -- i.e., find Antares and set the RA, then set the RA/Dec for Polaris and move the mount, repeating until no alignment change is needed.

Because I now knew what I was looking for (to me T Lyr is a deep red but dimmer star), I was able to recognize T Lyr off to the side of the magnified field of view after using the setting circles. In finder mode there was no indication of the star. Later, I tried the same technique for carbon star RR Her (16h4m, +50.5d), but because this star is not very red, I had to use an atlas to find it (it also was off to the side of the magnified field of view).

These exercises confirmed, to me, that the Questar setting circles are just fine for locating bright objects like Saturn or distinctive objects like globular cluster M92 (in Her). The setting circles are also good for areas where there are not too many stars visible because of light polution -- but I am located where I can see the Milky Way, Andromeda Galaxy, and Lagoon Nebula/Cluster (in Sgr), all with the naked eye, so that star-hopping works just as well, maybe faster, than the setting circles. HOWEVER, if the object is rather small and perhaps nondescript at lower magnifications, then a decent star atlas may be needed, paper or electronic. Locating a double star in a field of several, or a small planetary nebula, or confirming an asteroid sighting, are typical situations needing a good chart.

As mentioned in an earlier post, the S&T Pocket Sky Atlas (PSA) doesn't work for me, perhaps because skyglow dims what is seen in finder mode, and the narrow, detailed field in telescope mode has too many stars. For me, I have now found that Taki's 8.5 Magnitude Star Atlas works, and I suspect the S&T Sky Atlas 2000.0 would be similar. Maybe the PSA would work at a very dark sky location where the finder shows more -- I don't know. And for some observers I am sure that an electronic atlas would also work just fine.

I haven't seen any posts on what star atlas others may use, so I strongly suspect that many Questar users are primarily SLAP (solar, lunar, and planetary) observers, perhaps including a few brighter Messier objects.

Sooooo ... has anyone else viewed carbon star T Lyr using their Questar? Probably not...

#9 justfred

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Posted 23 August 2012 - 03:30 PM

Ah, Jim. My interest is piqued and tonight promises to be clear (at least according to the CSC Sage). I'll take the Q out and try my luck at T Lyrae. I agree the finder will find itself lacking in the Mag 7.5 to 8 range - especially in my suburban setting. Will take my Atlas 2000 with me just in case. :) This will be fun.

Thanks for the challenge.

Will let you know how it goes.

Fred

#10 justfred

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Posted 24 August 2012 - 09:52 AM

Jim,

I took the Q out and viewed T Lyrae last night. I used the setting circles but must admit that if I had not used the Taki chart I may not have found it at all and definitely would not have found it as fast. I also had the Atlas 2000.0 but the Taki was all that I needed. I used the Brandon 24mm to find the star and then used the internal barlow to view it. This is the first time I have seen this particular Carbon star and I was impressed. With that eyepiece it was small and not very bright, but really red.

Thanks again for the challenge and the mention of the charts. I downloaded the chart PDFs to my Windows phone. In my suburban setting the white light is not an issue, especiall on the dimmest setting. At a star party I'll have to use the hard copies.

The whole session took less than 30 minutes, from grabbing the Q and walking out, to setting the Q back on the shelf in my office. It is the epitome of grab-and-go.

Fred

#11 JimK

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Posted 24 August 2012 - 05:33 PM

Wow. Fantastic. I am *so* glad that you got to see and enjoy carbon star T Lyr as much as I did.

I am glad that the Taki charts worked for you, too. They can provide that roadmap between the finder mode and telescope viewing of certain objects. A few charts can be printed at a time, and since they are a PDF file, some readers allow for enlargement and printing of just a small section of a particular chart.

Yes, the Questar is a great grab-n-go. For my last few viewings the clouds came in fast and ended my session only an hour after I ventured out. Rapid setup/takedown allowed me to see the most. Now I just have to wait for either the rainy season to end, or for an evening break in the clouds, so that I can track down more sky gems.






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