Monday, 3 October 2016

1.-2.10.2016 - A night in Hartola

Telescope: 10" GSO
Obs. place: Hartola, Finland
Date: 1./2.10.2016
NE Lim.mag: 7.0 (zenith)
SQM-L: 21.40 (zenith)
Background sky: 7/10 (fairly good)
Seeing: 7/10 (fairly good)
Transparency: 7/10 (fairly good)
Weather: +9°C - +2°C, humidity 74-90%, 1010 hPa, W wind 3-8 m/s, clear.

Around 7 pm the sky was still covered in clouds
Around sunset the weather still looked pretty gloomy but in the end the sky was clear at around 9.30 pm. It was also the proper first light of the new 10 inch GSO. I have used the telescope a few times before but never under darker skies.

I was fairly well armed, however had no laptop or additional sky charts with me apart from Uranometria which proved to be a pretty bad idea. I struggled to find many of the fainter objects as they were not immediately visible.

Without further ado here are some of the more uncommon described as I saw and experienced them. I will add the drawings to this post later on when I have the sketches processed.

Palomar 10 (altitude ~46°)

Despite my best efforts I could not see the globular cluster. I was exactly at the right position but could not pick out anything that resembled a glow.

Uwe Glahn reported Palomar 10 as "very faint, difficult to detect" using a 16" telescope. Iiro Sairanen described the object "very faint haze without clear shape with extremely averted vision at 176x" with a 18" telescope. So with this mind, I suppose it is forgiveable that I could not pick it out.

Messier 57 central star (altitude ~55°)

During few fleeting moments I could just see the central star @ 357x but not with any magnification below that. I managed to see a magnitude 15.3 star close to M57 fairly easily as well as a magnitude 15.7 from time to time. My previous sighting on the central star was back in 2008 using 12" GSO. My notes say: "central star was invisible @ 429x but fairly easily spotted @ 600x".

NGC 6826 outer halo (altitude ~71°)

Surprisingly easily visible as a 2' circular ring surrounding the "actual" NGC 6826 @357x. I also suspected a slightly brighter spot on the NE side of the outer halo. This seems so collaborate with a small knot visible in photographs.

IC 4677 (altitude ~66°)

Invisible without a filter but with Lumicon O-III almost shamefully easy. NE-SW elongated blob nearly midway between NGC 6543 and PPM 20675.

Veil nebula complex (altitude ~56°)

Stunning view. I did a rough sketch showing several fainter components visible in the region. Simply by using Uranometria I was able to spot at least 17 different components in the Veil nebula. Looking at a map @ Adventures In Deep Space (by I could see all the marked components apart from "B" even without a proper map of the region.

Palomar 1
(altitude ~80°)

Finally got this sucker! As soon as I found the Big Dipper-shaped asterism just north of Pal 1 - I knew I was gonna get it. However it was a lot more difficult than I had expected - same problem as with Palomar 10. I appeared as a tiny 0,5' circular glow without detail.

Abell 6 + PK 136+5.1 (HFG 1) (altitude ~70°)

Despite interference from an annoyingly bright HD 18137, Abell 6 was fairly easy to see using a O-III filter. HFG 1 was a lot more of a challenge only barely showing a 6' irregular/circular glow.

Pegasus dwarf / UGC 12613 (altitude ~42°)

Fairly bright, visible SE of a Y-shaped asterism as a 2' x 1' NW-SE elongated glow without a nucleus.

 NGC 604 (altitude ~59°)

I got inspired to view this object again after seeing a sketch made by Riku Henriksson at the DSA. Riku's sketch is an excellent representation of what I could see with my telescope - apart from the actual individual stars. There was "a string of stars" [without the stars!] visible in the NW section of the nebula as well as a stellar brightening visible in the southern section of NGC 604.
Cassiopeia A (altitude ~75°)

Cassiopeia A was the final object of the night. I was nearly certain I had no chance of seeing it but the 10" GSO proved me wrong. I had to wait for nearly 1.5 hours for it to climb down from zenith for a proper look. It took me quite a while to find the correct position but once I did... bang. Using a Lumicon UHC filter a circular glow was nearly instantly visible with averted vision at the exactly correct position. Cassiopeia A has been seen with an aperture below 10 inches but seeing it with the GSO from a place such as Finland is quite nice.

Morning mist

At 4 am the telescope started to look and feel quite damp so I decided to head back in.  All and all the weather was decent, although humidity started to rise to unbearable levels around 4 am as the winds calmed down. Despite it it, Messier 33 visible with the naked eye and I was very happy that I managed to avoid the forecasted Aurora Borealis display.

Full list of objects observed. Asterisk (*) = sketched.

Collinder 399, NGC 6802, Cr 399, Palomar 10 (negative observation), Messier 71, Messier 57(*), NGC 6826(*), IC 4677(*), NGC 6910, NGC 7027(*), NGC 6888(*), Veil nebula complex, Palomar 1(*), PK 80-6.1 / Egg nebula(*), NGC 7000, NGC 6991, Messier 39, NGC 7026(*),  NGC 7048, Stock 5, NGC 886, Abell 6(*), HFG 1(*), Pegasus dwarf(*), Messier 33 (naked eye), NGC 604(*), NGC 1 & 2(*), NGC 16, NGC 22, UGC 69, Andromeda galaxy, NGC 206, Messier 52 + Cz 43, NGC 7635 / Bubble nebula(*), Cassiopeia A(*).