PDA

View Full Version : Observing Palomar 1



Ernie Ostuno
July 18th, 2018, 07:41 PM
Last night we had some really clear skies with low humidity and no haze, which is unusual for Michigan in July. So I attempted to observe Palomar 1, a very faint globular cluster in Cepheus. At 375x with the 13.1", I was able to see a small fuzz with averted vision at the spot where the cluster is located on the photo chart. However, I got the impression that what I was seeing was a very faint star, since the "fuzz" seemed to have a high surface brightness. There is a faint star (around 15th magnitude) on the photo chart near the center of the cluster. My question is, is this star a cluster member or a foreground star? The object was too faint and small to determine whether I observed just this single star or the combination of other very faint cluster members. I'm interested to hear from anyone who has observed Palomar 1 and whether they were able to discern the haze from this apparent foreground star. Also, if you could include the aperture and magnification you were using. Thanks.

lamperti
July 18th, 2018, 10:40 PM
With a 20" at 272x. "Seen with direct vision under a triangle asterism. I needed the Millenium Atlas to star hop. Maybe some resolution of a couple of stars. Class X-XI." (actually a Class XII)

Steve Gottlieb
July 19th, 2018, 07:45 AM
The brightest star in the center is referred to as Pal 1-C in this study (https://arxiv.org/pdf/1107.5315.pdf). The authors list a V magnitude of 16.6 for Pal 1-C ("transformed to the Johnson system from the HST system") and also mention "membership of this object is not as certain as the others". Two other stars in the halo are just slightly fainter (V = 16.7 and 16.8). I can't vouch for these magnitudes but they seem reasonable, comparing the trio in Jimi's 48-inch.

Bertrand Laville
July 19th, 2018, 10:35 AM
Hi All,

Here is my drawing of Palomar 1, with an 25" Obsession.
The cluster was seen as a very weak, hazy patch. I suspected somme daazzling lights on the halo, but not sure.
Brian Skiff gives the brightest star at m 16,3v,
Detail report at*: http://www.deepsky-drawings.com/pal-01/dsdlang/en

By the way, here is a survey of all Palomar clusters.
http://www.deepsky-drawings.com/category/catalogue/b-catalogues-specific/b1-groupes-etoiles/1-palomar/dsdlang/en

Clear skies
Bertrand
http://www.deepsky-drawings.com/dsdlang/en/


3135

Ernie Ostuno
July 19th, 2018, 06:55 PM
Thank you all for the observations and background information on the cluster. I think what it comes down to is whether the star Pal-1C is part of the cluster, because I am pretty sure I observed that star, but not at all sure I detected the light from any other stars in the cluster through my scope.

This situation is similar to my observation of Palomar 4 a couple years ago. I am sure I saw several of the brightest stars in the area of the cluster, but wonder if they were truly cluster members. Here's the Hubble photo of Palomar 4 (https://en.wikipedia.org/wiki/Palomar_4#/media/File:Palomar_4_HST_10622_01_R775G555B475.png). Notice the five brighter, reddish stars. Are they red giants that belong to the cluster? Or just field stars?

Now compare the Hubble photo of Palomar 1 (https://en.wikipedia.org/wiki/Palomar_1#/media/File:Palomar_1_Hubble_WikiSky.jpg). Are the brighter stars (including the center one) cluster members? I am going to have to carefully observe this object again on an optimally clear night to see if i can discern any of the other stars besides the central one.