chiltonstar

Keep up the good work Nick!

I wonder if we need to name/rename a cluster "The Hedgehog" as they seem to be associated with observing a lot.....

Chris

On 25/08/2019 at 08:04, Stu said:

A great night Chris. Some real toughies there you got. x450 is pretty impressive, interesting how the seeing is often much better when there is hazy cloud around. I shall add these to the challenge list for the f8.

I would have thought that your f8 rocket launcher would manage these with ease,  if collimated Stu?

Chris

Well spotted! Interesting that Uranus appears white with the 20 inch - I wonder if it would be its more normal colour if the mag was higher?

Chris

Last night, the seeing here (Oxford) was excellent, some cloud though and some hazy cloud moving across from earlier con trails, but it looked like a good night for close doubles!

I set up the 180 Mak on the SkyTee2 and headed for Pi Aquilae for starters. Beautifully split at x270 (10mm baader Ortho), with a shrap Airy disk and diffraction rings. Always an absolutely beautiful pair.

On to Astronomy Now's doubles for September, starting with 1 Delphinii. This is a close pair, sep 0.9 arcsec, mags 6.20 and 8.02 and seemed quite a challenge. At x270, it is obviously a double and split, but much more obvious at x450 (6mm Ortho), and nicely resolved. Good to have an evening when x450 was possible and gave a sharp Airy disk and razor sharp diffraction rings.

STF 2690 (also AN) is next door to 1 Del and an interesting one. Visibly at x270, it appears to be a wide double (17 arcsec), but at x450, the westerly star of the pair (B component I think?) was decidedly oblong. Both of the two components are in fact doubles apparently - a very close double-double for big scopes?

I finished with Lambda Cygni - always a tricky little devil at the best of times (Mags 4.73, 6.26, sep 0.90, PA 358 degrees). At x270, it was visibly split with two apparent disks; at x450, more detail was visible with the secondary more like an egg shape on the diffraction ring. I've attached two simulations (Aberrator) of this double for the 180 Mak, one at lower mag and one at high mag which are very similar to the eyepiece view I had with the two Baader Orthos.

Always a pleasure when the scope can be pushed to x450 (65x per inch) and still be sharp!

Chris

I occasionally resort to music while observing, usually Tomas Luis da Vittoria or JSB.

Chris

1 hour ago, Mark at Beaufort said:

That is really good. I tried to produce a similar arrangement for my Skywatcher Heritage 130P. Whereas the Alt scale works reasonable well the Azimuth scale is fixed so I only get a rough idea of the degree position before moving the scope.Photos attached.

A good arrangement - you're circle cutting skills are obviously better than mine!. I use the setting circles on my EQ mount (Vixen SP), but to be honest, it's not that convenient with the 180 Mak due to lack of rings - I tend to end up in some very odd positions trying to observe, and for this reason, an Alt Az arrangement is easier (on the neck!).

Once the az circle is set to true geographic north, it remains fixed and the calculation of current alt and az is done by Skysafari - so convenient, unlike EQ setting circles where the RA scale has to be adjusted all the time.

I wanted an accuracy of <1 degree because of the limited FoV of the Mak, and this seems to work.

Chris

On 16/08/2019 at 08:27, jock1958 said:

I’m intrigued by your DIY azimuth circle for the Skytee 2 & Wixey. Any chance of a pic please @chiltonstar ?

Now posted in DIY forum, as requested! More details available if you need them, and the image of the 360 degree scale I used.

Chris

Posted by request!

After some rather annoying evenings using my normal star hopping method, frustrated because of the 70-80% cloud cover so I had very few reference points to start from, I decided to construct a simple Az setting circle, and add a Wixey inclinometer so that I could get accurate enough alt-az settings to get to the right part of the sky, even when partly clouded!

The az scale was an image of a 360 degree protractor (using macro lens to retain linearity) enlarged to ca. 200mm diameter, printed on thin card and then laminated onto 1mm high-density waxed card (aka pizza base) and covered with plastic stick-on film. To get it to be relatively stiff to turn, I added a disk of high density foam on it to grip the 100mm non-rotating base of the Skytee. The pointer is a miniature laser pointer, with a disc of blue acetate over it to reduce the intensity. It is mounted on a small aluminium bracket to avoid fouling the slomo knob, and the angle can be adjusted up or down to centre on a larger or smaller scale. It is fastened to the Skytee on a flat surface using velcro.

Alt uses a normal Wixey with a magnetic base, clamped in the top mounting position on a ferromagnetic plate.

Modus operandi: level base, find a star somewhere in the right area of sky and centre on it. Zero the Wixey on a level surface and clamp it in position. Using Skysafari (settings adjusted to horizon coordinates, ie alt-az) read the az value and set the scale to that by rotation. Loosen the mount clamp for the top mount and move the Wixey and clamp in the alt axis until it reads the right value for the star (again, from SkySafari) and clamp. Then just "push-to" the right coordinates for the target!

Accuracy and repeatability? I've managed to use it twice so far (alas, the climate), both times finding Neptune in a partly clouded sky, once using the Moon to set up and the second time using Vega. On both occasions, Neptune was in the finder view (9x50 RACI) about 0.5 degrees from the centre.

To increase the readability of the az scale, I'm working on printing out a large enough disc to lay on the ground, just outside the tripod legs.

Some pics below....

38 minutes ago, Geoff Barnes said:

Not here Chris, another 12 hours away down here. I'll be happy to see anything after 2 months of cloud to be honest!

...ah yes, of course! Always a bit difficult to get one's head around the view and timings from the Southern Hemisphere.

Chris

2 hours ago, Geoff Barnes said:

I'm getting cautiously excited! Clear blue skies and gentle winds at 4.30pm, could this be my first chance for 2 months???

GRS due to be centre stage between 9.30pm and 10.30pm, I'm going to throw everything I've got at it up to 375x with the Vixen SLV 4mm and see what's possible.  

....and a Europa transit if I'm not mistaken! Too low for us near the North Pole but you might see it Geoff?

Chris

48 minutes ago, jock1958 said:

I’m intrigued by your DIY azimuth circle for the Skytee 2 & Wixey. Any chance of a pic please @chiltonstar ?

Nothing very original or sophisticated, but effective. I'll take some pics and post it in the DIY forum.

Chris

I caught a glimpse before Jupiter set in the trees - the seeing here was poor to average, but high cloud made things difficult. Saturn seemed to come with a cloud attached last night which tracked it for some time - very annoying.

I tried out my DIY azimuth circle for the Skytee2 mount and Wixey to find Neptune which was in a clearer patch of sky. Straight to it within 0.5 degrees - a very nice view, although too much background haze and Moon to have a chance at Triton though.

Chris

My starting EP with my 180 Mak is a 40mm Plossl; the field of view is limited, but it works well when looking for DSOs which fit within the field of view. I have a 56mm Meade as well, which is good for showing objects like fainter galaxies, but there some optical issues.

As stated above though, the 180 Mak is primarily a planetary/double star/lunar scope, for which it excels! The views last night of Saturn at x350 were amazing.

Chris

10 hours ago, Mark at Beaufort said:

Fantastic stuff Stu - I have still not split Zeta Hercules despite using many different scopes. I thought I might crack it with my 180mm Mak/Cass but unfortunately not. Clearly I must persevere.

I would say I've found it a lot easier with my 180 Mak than with my smaller scopes. I've not imaged it with the 180 Mak yet, but a simulation for different apertures shows how much better it is resolved at 180mm aperture - this closely matches the visual impression.

Chris

1 hour ago, Rob Sellent said:

 

Also nice to hear about your 8" f8. That really must be a lovely scope and rather unique. I mean, I've seen 8" f5s and even an f6 but never an f8. It's a real shame these types of OTAs are no longer in production. In terms of resolution, I imagine it'll out perform most 4"/5" ed or apos and in terms of contrast must also give the more exquisite glass types a run for their money. 

I imagine OOUK might well be prepared to do a production run of 8" f8 tubes if they thought there was a market - for example ten of us signing up to put in an order???

Chris

39 minutes ago, Stu said:

 

I'm sure it can be done with a smaller scope with excellent conditions; a good mak or refractor which, as you say would produce nice tight star images would be an option. I'm not sure what the limiting aperture would be though, perhaps @chiltonstar Chris can help here?

The 8" f8 I'm using has high quality optics and a very small secondary obstruction and so it performs somewhat like a 6" apo refractor although it does obviously still show diffraction spikes on brighter stars and planets. It certainly worked for me last night!

Great Stuff Stu! What a fantastic scope by the sound of it!

I've certainly split it with my 127 mak (true aperture 119mm) - smaller than this the secondary will merge with the diff ring of the primary I imagine, but maybe still visible in nights of exceptional seeing. This is a stacked image of Zeta Her with my 127 Mak, together with a simulation using Aberrator for 119mm aperture:-

Chris

I have my 180 mak on mine usually, or my 102mm f13 frac (Vixen objective) which is a beast to mount and needs something fairly "industrial" to mount it on.

It is worth adding that the second mounting position (top) on the SkyTee is for lightweight scopes only such as a small frac - I put my ED80 on it, eg below:-

Chris

1 hour ago, Piero said:

Great report! 

Saturn was wonderful last night and the seeing was reasonably good here too. 

Enceladus was visible in my new dob. Nice one!

How big?

Chris

6 hours ago, Geoff Barnes said:

Well done Chris, Enceladus is a tough target alright. I've seen it a few times when the seeing has been excellent with my 12 inch Dob. but more often than not it's invisible. I must try your technique of getting Saturn out of the way to make things easier!

It's the technique I use for fainter secondaries of doubles, and for moons eg of Uranus.

I suspect that now I've seen Enceladus, it will be easier to spot in the future - bit like Sirius B!

Chris

I have been looking for Enceladus all through this Saturn season, without success until now!

Last night, the conditions were right, Saturn was beautifully clear, Cassini razor sharp and the relatively good transparency reduced the haze around the planet and made the colours of the disk much richer creamy-orange. Also, Enceladus (mag 12.3) was due W of Saturn in a favourable spot. Moving Saturn out of the field to the E with the SkyTee2 slomo knob, and then allowing it to drift back into the field of view showed Dione (mag 10.9) first as a bright pinpoint, then shortly after and just before Saturn itself appeared, the fainter little point of light of Enceladus itself. It was bright enough to be direct vision, although with Saturn in the field of view, it wasn't visible even with averted vision. I repeated this a few times before going on to look for as many other moons as I could see.

The scope was my 180 Mak, EP a 10mm Baader Ortho (x270), with the ADC in place.

SkySafari screenshot adjusted to match the eyepiece view (laterally reversed).

Chris

When conditions are excellent, the view can be stunning as you clearly found! Although these light, humid and hazy evenings are not to everyone's taste, they do bring out the best in Saturn and Jupiter don't they?

Chris

27 minutes ago, Geoff Barnes said:

I've just been having a bit of a play with SkySafari and it seems to me that on 31st October 2024 at 9.30 pm in the UK Saturn will be at about 40 degrees altitude. That should be good enough for a decent view for you I would think.  

Something to look forward to, Deo volente.......

Chris

I caught it for 15 mins between patchy cloud and rain which was moving across., using my grab 'n go (127 Mak, 8-24mm zoom and Vixen Porta2 mount). 

The GRS was very clear and well defined, with Io intermittently visible above the GRS and the sharpish shadow close to the edge of the disk. Unfortunately as Jupiter started to set behind some pines, the seeing went to some extent so I headed back inside.

Well worth the look though!

Chris

Simply amazing images, as ever!

Are the sites you go to chosen for their seeing (if so, how do you select), or simply stunning places you like going to?

What a beautiful object Jupiter is....

Chris

For the first time, I saw a blood red Jupiter last night - two combines were working a few hundred metres S of me, and producing a huge cloud of dust. Powdered wheat doesn't seem to work as well as thin cloud though for improving seeing....

Chris