Fullerscopes 4" frac 14th April 2010

[philj]

Heres an entry from my log last night, this was the second light with a Fullerscopes 4" F15 Refractor 1970s vintage, it was mounted on a 120 year old Cooke Mount with no motors goto etc so it was observing old style:D

14th April

A surprise clear evening, again work next day prevented me from spending the required time for imaging with my main rig so I got the Fullerscopes 4” F15 refractor out mounted to the Cooke mount for a bit of visual. I also wanted to check out the adjustments on the scope I had made the night before.

Venus was low in the West but I could not see Mercury from the observing position.

I spent a long time on Venus and used red and blue filters to good effect. Once the planet cleared the trees the image was quite stable at times and I even managed to push 270x. I don’t know if it was my eyes but Im sure there was a slightly darker area in the disc which I could detect in both red and blue but it may have been just the contrast between the bright edge of the disc and the centre, difficult to tell.

Saturn. I spent ages on this planet as the image was very stable, more so than Monday nights session. I was pushing 270x with ease at times but found 170x an easier mag due to the brighter image affording better views with filters.

Titan was close to the planet but I must admit I could not detect any other moons for some reason, even when the skies had darkened fully but I did not go out of my way to search for them as I was transfixed with the image of the planet that the scope was giving me. I would say that this view was easily on a par with my Meade 127ED Apo, albeit slightly dimmer but just as sharp.

Out of the filters I tried I found no11 Watten to be the best affording wonderful detail in the rings, even though they are almost edge on you could tell there was more than one but I could not make out Cassini Division though, I reckon I would need more magnification and aperture to pick that out at the moment. But you could tell that the rings were definitely plural as there was subtle brightness changes to them either side of the planet. The ring shadow across the disc of the planet was a sharp fine line and the shadow of the planet on the rings was easy to see.

The poles were nicely picked out with subtle shading changes lending a 3d feel to the image. 2 cloud belts were easily visible and a third could be seen at times. Altogether I think I spent an hour looking at this planet with different mags and filters because the image was just so nice.

Mars was high and bright and required some manoeuvring and scrabbling about on the floor, (I am in the process of making a 12” extension to the tripod which should help avoid much of this in future).

At 170x with the No 12 filter the image gave a small but pleasing view showing the polar cap and 2 definite dusky areas as well as the obvious gibbous phase of the planet. Unfortunately not having RA drive and the difficult observing position made keeping the planet in the fov at 270x difficult so I did not get to try this mag filtered but the sight in normal light was very nice indeed. The polar cap was obvious and one of the dusky markings had the clear shape of Acidali and the other I reckon was Meridiani as it was running at an angle across part of the disc opposite Acidalia.

Aplogies to Mars experts if I have the names wrong but Im no expert and each map I look at seems to name them differently.

22:15 and I decided to drag myself away from the planets and have a quick look at a couple of doubles, Castor split nicely with a very obvious magnitude difference. I then tried Polaris and the companion was easily picked out, (both views at 170x). My double star repertoire at this time of year had run out at that so I fitted a 25mm ep and had a bash at a few DSOs.

The Perseus double cluster with long fl refractors tends usually to be a little bland but I was surprised with the view this time. Both elements fitted well within the fov of the ep and they were acceptably bright showing obvious colours in some of the brighter component stars.

M37 was dim but resolved nicely into hundreds of stars, M36 good but compared to m37 its not as spectacular in any scope. M35 was nice with the smaller fainter cluster just visible on the opposite side to the bright star on the limb.

I then decided to reluctantly pack away at 23:15 as I need to get up early for work the next day. Altogether a very satisfying night observing the old fashioned way:D

Phil

[DarkerSky]

That's a brilliant report Phil. Sounds like a fabulous evening. Really intrigued about the possible shading you saw on Venus. First report I've heard this year. I have seen shading myself on Venus close to the terminator in the past - I know how difficult it can be to say for sure that is what you are seeing as the differences can be very subtle.

btw - how did you get your hands on the cooke mount?

[philj]

Cheers Darkersky. I was out last night with teh scope and had another look at Venus but just couldnt see anything like it, so if it was cloud markings / shadows I sont know. Thats the problem with visual on venus even in stable conditions the image is still active.

The Cooke mount was a win in a local auction, it was part of a lot with an antique scope and the listing didnt mention the mount I was very lucky and pleased:D

Phil

[Doc]

A great detailed report Phil and one that shows lots of promise for the scope, it's a bit starnge you couldn't see more then one of the Saturian moons, I would have thought you would with that scope.

[philj]

Hi Mick, I wasnt really trying that night, teh night after I went out specially to find them and caught Titan as before and Rhea with averted vision and at times I thought I could see some others but could not be sure. Its funny because I was splitting double stars with very faint companions that were near the scopes theoretical performance OK but saturns moons were just that bit elusive. I shall try again next clear night and this time arm myself with teh netbook running skymap.

Phil