markse68

Beautiful sketch and amazing catch Achim! A little bit scary- that must be many earth diameters long? How long would a prominence like that last?

interesting-I guess it really has become a phenomenon- there was an article in the Guardian Weekend mag last weekend about amateur telescope makers! 

https://www.theguardian.com/science/2020/jul/25/meteor-go-by-everyone-gasps-most-dedicated-stargazers

poor old forgotten Pluto 😢😉

Congrats though Stu- real staying power and perfect night for it

Mark

Looks great from here Dave  Nice feeling to finish a project like that- congrats

Mark

Good stuff Nige- sounds like you had better seeing than I had here in London but you’re definitely right that the longer you look the more you see! Strange the GRS looked grey- I was too busy looking at the moon and waiting for the ISS transit that missed (🤦‍♂️) that when I turned to Jupiter it had almost fallen off the limb.

Mark

1 hour ago, BGazing said:

Played the whole night with ADC and binos on C8.

The amount of lever correction needed with 1.25GPC is tiny, but results in a detectable improvement. Moons are elongated dispersion dots and when corrected become dancing fuzzballs (seeing, meh) without dispersion. One can also see AD on the Moon this low, while cruising top part it has a sliver of blue fringe (very thin) and the corresponding orange sliver at the southern pole.

Seeing was not that spectacular, tbh, but what can one expect at 23 degrees in meridian.

Interesting. Seeing wasnt great here either last night- I guess all the heat from a very warm day didn’t help but I also noticed that very little correction was needed on the planets and it didn’t make any noticeable difference in the moon. I wonder if AD effects are inversely proportional to seeing quality? I guess if the ad is swimming around stirred by poor seeing then it’s not a fixed quantity to be fixed with a corrector? 🤔

I found mention of these on another forum and thought i’d check them out as they sounded interesting! 

First up was 49 Cyg- an easy 2.7” double with one lemon yellow star and a grey blue companion- very pretty 

Upsilon Cyg is meant to be a binary according to SS but it looked like a triple- I guess the third may be line of sight. A piercingly bright steely blueish primary star with 2 tiny pinpricks nearby. I don’t know if it was the brightness of the primary but it seemed to be in a haze of nebulosity- bit like when your ep mists up but i checked other stars nearby and they didn’t show this 🤷‍♂️

Tau Cyg was a bit of a challenge. 1” separation according to SS- I could make out a telltale brightening of the first diffraction ring with my highest power ep- 3.5mm but it wasn’t convincing. So I barlowed it for a whopping 914x (🤦‍♂️) and that did the trick- a satisfying clear split but still tight. Similar orangey colours and smaller secondary.

I also tried for BU 1133 which is meant to be a 1.1” double. It took a while to find but I think i found it but it was a much dimmer star than the others and no sign of its pair. Maybe I didn’t find it after all? 

Seeing wasn’t the best tonight- only a 1 or 2 Plato craterlets night and Jupiter and Saturn have looked much better of late but a satisfying night nonetheless. The weather we’ve been having lately it was a bit of a relief to be out there at all and it was t-shirt temps most of the night so that was nice too 👍

Mark

Edit- had another look at Tau Cyg and the secondary is a different colour to the primary- the primary was more yellow than orange and the smaller secondary slightly blue/greyer.

Mark

9 minutes ago, John said:

What scope were you using Mark ?

It was my old faithful 8” f8 dob John

I had a go at the double double tonight- it’s been ages since I last looked at it. I had a clean split at 80x with my 20mm ep and it was split at 64x with my 25mm ortho but I find with bright stars and longer fl eps that I get a kind of flaring almost like astigmatism and i’m not sure what’s the cause- it may be my eyes I guess. It’s not the star shapes as such but some optical anomaly i think that prevent splitting at lower powers

It missed!

9 minutes ago, HollyHound said:

Lovely book... I bought this last month, at the same time as getting Luna Cognita (which is also a fantastic book BTW). Just for information, I got mine from Amazon for £12.99, but the Royal Observatory Shop is indeed a tad cheaper, and direct of course 👍

ebay £10.83 delivered- just ordered

23 minutes ago, johninderby said:

Couple of mods to the Altair ADC.

Replaced the supplied eyepiece holder with a TS one as the original one took a lot of force to insert an eyepiece. The TS is the same height.

Wanted to be able to rotate the ADC so fitted a short eyepiece holder to the diagonal and shortened a T2 nosepiece in the lathe to suit.

Found the black adjustment levers hard to see in the dark so replaced them with some chrome M2.6 standoffs which should show up better.

have you used it yet then?

new pair of cheap binos- pretty sharp once the grease was cleaned from the eps, nice and light and noticeably brighter than my jenoptems but a bit bulkier- shall try them tonight

5 hours ago, Geoff Barnes said:

I'm staggered by this, 49x??? Whilst the double double is very low down here near the horizon and very wobbly, I have just about managed to split them into four on a couple of occasions with my 12 inch Dob but only with around 180x-200x.

I bet you have no trouble with Antares though!

This does sound like a very enjoyable summer evening pursuit  and shamefully not one i’ve ever done- I skipped the recommendation to start with binos and  consequently my sky geography is lacking and I should remedy that! I’ve been obsessing over vintage binos lately so most surely will!

Lovely job and I like the colour too

Main mirror looks in good condition considering the state the exterior was in!

My Tal-1M was what got me back into this pastime a bit more than a year ago. Haven’t used mine in a while but it’s a lovely piece of kit. I stepperised mine so I could run it off a Makita battery out in the field and it worked nicely- it’s very pleasing to be able to aim it and then not have to keep tweaking the slomos particularly at higher powers. I used tape too for the focuser.

Enjoy!

Mark

Trouble is with the screw lock type the screw is a small thread so will always likely feel it has some play. But you could buy quality like moonlite or feather touch etc or I imagine these from baader have nice quality screw locks if you don’t want the expense of click lock

https://www.firstlightoptics.com/adapters/baader-2-to-125-reducer-adapter.html

or cheaper still

https://www.rothervalleyoptics.co.uk/baader-pushfix-2-125-reducer-1mm-optical-length.html

Im quite tempted by the last one- really low profile and if the screw lock is anything like the 1.25” to T2 baader adapter i have it’ll be silky smooth and play free. I don’t know if they use a plastic insert or sticky grease but it’s very pleasing to twiddle

If you want the ultimate screw lock type there’s the Glatter Parallizer 

https://www.firstlightoptics.com/adapters/howie-glatter-parallizer.html

which I hear is really good (made by feather touch)- it has ingenious “V-block” grooves machined in the walls which lock the ep and adapter into perfect axial parallelity in the focuser tube unlike all others- bit spendy  though!

Mark

Mines my 3.5XW- gets used all the time for tight doubles and when the seeing is really stable it’s pretty awesome on the moon. Gives 469x in my scope. Was using it tonight trying but not convincingly to split Tau Cyg and BU 1133- too much breeze for a steady enough image to be confident of success. I’ve been using a 6mm ortho barlow/adc’d to 3 quite a lot lately trying for Antares but I’m getting the feeling i’ve missed the chance this year as it’s on its way down by the time it gets dark already and it never gets very high to start with. Will keep on trying though, hoping for miraculously steady seeing in some freak alignment of the forces 🤞

Maybe my new planetary ep? 🤔

(with adc of course 😉)

edit- sorry- it’s an ocular (not an ep)- says so 😂

What’s the advantage of the underneath mounting bracket over the side mount? is it just that it raises the scope a bit?

8 minutes ago, fwm891 said:

Thank you. I have a small lathe and milling machine so the parts were produced on those. Filter threads were cut on the lathe on a very trial and error basis untill I had the dial readings, then it was fairly easy to cut all the 42 x 0.75mm threads. Followed by the 48mm threads in the filter drawers.

Awesome work indeed then! I really need to get my head around thread cutting on the lathe- such a useful skill!

Looks really neat and beautifully made- was it done on a CNC or did you machine it by hand? And how did you cut the filter threads?

I think the material the bags are made from has quite a high melting point- you could probably dry them in regular oven set at 100degC. Or just buy new ones- they’re pretty cheap. Microwave might work but you really want dry warm place- if the moisture can’t escape well enough it’ll just be reabsorbed or not evaporate at all? Your coffee brewing might hinder the drying process

15 minutes ago, bomberbaz said:

googled lens plural, what a tin of worms that is 😅

What’s wrong with lenses? 🤷‍♂️

28 minutes ago, PaulM said:

I use the app from here gives a good view of clouds via radar 

https://www.weatherandradar.co.uk/

Thanks for all the other suggestions but this one from Paul looks just what i was after- can zoom out and pan to get a better look at what’s going on- brilliant! Thanks Paul  Will be double checking on the met office from now on! (doesn’t look like they’re wrong for tonight though  )