Saturday 23rd Jan - Uranus, Moon, Orion doubles.

[MercianDabbler]

After reading a few reports of good conditions on Friday night I decided to brave the cold, live with the moonlight and cart the SP102 outside for a couple of hours yesterday evening.

I set up further down the garden than usual to avoid my silver birches which interfere with the view to the south. The mains extension lead just about reached and I mostly managed to avoid tripping over the various garden features that make this a rather cramped location. I just did a quick levelling and polar alignment with Polaris vaguely near the centre of the polar scope. I didn't bother with the RA drive but still needed power for my makeshift dew heater. The final setup step was to fine tune the Rigel finder's aim... on Rigel of course.

First target was Uranus. I wanted to star hop from Mars but (again) could not reconcile the picture in the TV 32mm Plossl with Stellarium. After a few attempts I resorted to the setting circles and found the target easily. I wasn't sure if my scope would show the disc but put the 5mm Starguider in. I think I was seeing the disc - it definitely looked more disc like than out of focus blob like. Sweeping back to Mars I tried to figure out why my star hopping wasn't working. I think the problem is one of scale - I just don't have a feel for how the view in the tablet version of Stellarium should scale to what I see in the EP, likewise whether I should see more or fewer stars when looking through the scope. I lingered for a while on Mars but found it pretty unrewarding. As usual I could suspect a few smudges but no more and there were colour fringes on either side of the disc.

Next up was the moon with no particular feature in mind, just look near the terminator and see what looks most interesting. I found a very interesting looking area with some nice subtle ripples and then resorted to the tablet app (Moon Atlas 3D) to try to figure out what I was looking at. The app does simulate the effect of the Sun but it does this by just darkening parts of the image and does not show the effect of shadows from crater walls etc. so it's quite hard to reconcile with the real view. After much mucking about and checking orientation with the binoculars I got my bearings and figured out that it was Sinus Iridium. I tried both the 5mm Starguider and the 15mm SLV with a screw in moon filter. The SLV naturally had less magnification but I think I found the view more absorbing - Promontorium Laplace was particularly crisp. The need to swap the moon filter between EPs was somewhat of a disincentive to changing magnification.

The final item on the agenda was to try some more doubles in Orion. I'd downloaded the Coldfield Observatory list onto the tablet before going outside and found this very useful. It was easy enough to hop around with the Rigel finder. I did Delta, the Trapezium and Iota. Delta was very easy. I lingered for a while on the Trapezium trying different eyepieces but I think they all showed four stars once I had my 'eye in' and provided that I didn't clobber the scope. I was quite surprised at how much of the fishes mouth and the edge of M42 was visible through the 15mm SLV in spite of the moonlight. The 26mm Meade S4000 and 32mm TV Plossl showed some too, but less so to my eyes (shouldn't less magnification show more nebulosity?). Iota was a little more challenging. I started with the 15mm SLV and had to look a couple of times but once I'd spotted the fainter companion it was very clear, again as long as I didn't knock the scope. I left out Struve 747 because the Stellarium search wouldn't do that, Theta 2 which sounded less than compelling when time was getting late and Lambda (Meissa) because I'd done that on the previous session.

By now it was past 11PM and some high clouds were starting to intrude so I decided it was time to pack up. Checking the objective I found there was no evidence of condensation so my lashup dew heater had done its job with no need to make any further modifications today. My clothing layers had also functioned well, in fact I had to take a few items off because I was too warm during some parts of the session. I also was pleased to see Ursa Major standing on its end and well up to the east of north at the end of the evening. Previous sessions have seen it pretty low and closer to due north which is right in the worst LP from the city centre. I do find it pretty disheartening when LP stops me making out the plough properly but I shall now look forward to putting its galaxies back onto the target list for future sessions.

[John]

Great report, I enjoyed reading it

I sympathize re: your LP issues - I have the Bristol glow to the NE and the Newport / Cardiff glow to the SW so those horizons are not productive unless targets are well above them.

I find that using a bit more magnification does increase the contrast between the darker and brighter parts of the Orion Nebula as well. Last night 200x was wonderful for examining that central area (fishes mouth etc) with my 12 inch dobsonian.

 

[Zermelo]

3 hours ago, MercianDabbler said:

I just don't have a feel for how the view in the tablet version of Stellarium should scale to what I see in the EP, likewise whether I should see more or fewer stars when looking through the scope

Yes, I feel the same way.

One thing you can do is to adjust the extinction magnitudes of the stars in planispere apps, so that they better match your observing conditions. Last night, I could see few guide stars in my 6x30 finder, but having just the brightest ones showing in the app helps to match the views.

On the scale issue, I think it's very like how some people can use a terrestrial map to navigate car journeys successfully because they've done it a lot and they're used to the scale, while others (like me) don't judge the distances so well.  It will all come with experience.

[John]

1 minute ago, Zermelo said:

Yes, I feel the same way.

One thing you can do is to adjust the extinction magnitudes of the stars in planispere apps, so that they better match your observing conditions. Last night, I could see few guide stars in my 6x30 finder, but having just the brightest ones showing in the app helps to match the views.

On the scale issue, I think it's very like how some people can use a terrestrial map to navigate car journeys successfully because they've done it a lot and they're used to the scale, while others (like me) don't judge the distances so well.  It will all come with experience.

I sometimes find a 6x30 finder easier than a 9x50 for that reason. For more detailed and precise "hopping" the additional aperture and scale can be useful though.

As the seasons go by I do still need to remind myself of where seasonal targets are if I have not observed them for a few months. The first "hops" on a seasonal target can be a bit embarrassing

 

 

[Kon]

Excellent report and a very successful session you had!

8 hours ago, MercianDabbler said:

I just don't have a feel for how the view in the tablet version of Stellarium should scale to what I see in the EP, l

I found that using my 9x50 RACI it is easier to star hope. i tend to zoom in quite a bit in Stellarium and i sort of make my own hoping path using the nearby stars in the app and i try to match them on my finder. Once i get in the area i switch to my 15 or 25mm EP. As a beginner myself, i found that with the moon out it is harder to see some of the fainter stars that makes hoping a bit trickier but you start building some member for next time.