Aramcheck

Can you achieve focus visually through the eyepiece, on a distant object, in the daytime?

1st Moon pic with DLSR from 3rd March... It was an experiment to see if I could get APT to control the camera, which kind of worked. Image processed in PPIP + Registax (both 1st time use) + Pixinsight.

Not completely happy with it, but pleased to see the colour difference in Mare Serenatis and Mare Tranquillitatis when zoomed in.

28x1/100s @ISO100 - SW200dps + Canon 600d EOS

Cheers
Ivor

This posted on another thread by @Space Bat may help too:
http://astronomy.robpettengill.org/blindSmartPhonePolarAlign.html
 

I haven't tried it, but have read here on the SGL that the small cap on the front of the scope cap can be removed leaving the large front cap in place on the scope. That will cut down the effective aperture of the scope, but it can be rotated so that you avoid creating diffraction spikes. It will of course reduce the achievable resolution too.

Cheers
Ivor

If you can't see Polaris (& can't change set up location to one where you can) have a look at the Synscan manual section 11.3 (p37) on "Polar Alignment without Polar Scope".

It requires doing a 2-star alignment, then hitting "Menu"->"Alignment"->"Polar Alignment" & following the instructions to adjust the altitude & azimuth bolts. It's an iterative process, so you'll probably end up doing a couple of 2-star alignments & mount adjustments.

Cheers
Ivor

2 hours ago, Neil H said:

How to polar align when there is a house in the way ?

One way is to use an iOptron iPolar. eg: https://youtu.be/P69TpJM3p7U

Cheers
Ivor

Another alternative would be GIMP which is free.  Pixinsight also has a free 45 day trial which is fully featured. I tried that  in December & fell in love with the program. It's very expensive, but I prefer it to my ancient version of Photoshop.

Cheers
Ivor

10 hours ago, CaptainShiznit said:

One thing that didn't get factored in was the use of a standard light pollution filter though. Any idea how the use of one would affect the optimum sub length?

I assume it would depend on how much of light is transmitted. In the talk Robin Glover talks about the use of RGB & Narrowband filters requiring longer sub-exposures compared to monochrome, so I would expect the same based on the transmission curve of the filter:- https://youtu.be/3RH93UvP358?t=2904

Sorry - hit the wrong button on the keyboard....

The formula's for the noise calculation are from this talk by Robin Glover (Sharpcap) at last years Practical Astronomy Show: https://youtu.be/3RH93UvP358?t=58

I put them into a spreadsheet (attached).

Street lights are a pain!

Cheers
Ivor

DLSR Noise Calc.xlsx

32 minutes ago, CaptainShiznit said:

Would you mind me asking what your process looked like for working out such an accurate optimum exposure? I would love to replicate it. Cheers!

Thanks @CaptainShiznit

I had a play with the dataset, but couldn't achieve anything decent. To me it looks like you had stray light getting into the OTA & unfortunately the worst affected area is where the nebulosity is at it's greatest. Do you have any street or security lights that could be the cause of the gradient? I've noticed that on my 130pds light can also enter the OTA from the primary mirror end as well.

I'd also suggest reducing the exposure time & increasing the number of lights, which would make it easier to stack. I tend to shoot at 60sec, but unguided that is pushing it (EQ6). With my Bortle 6 sky I worked out the optimum SNR would be 127 secs for our Canon 600D... but subs of that length will have to wait until I've saved up for a guidescope.

Thanks for making the data available!

Cheers
Ivor

PS: with your set-up  does the focus draw tube extend quite a way into the OTA?

On 27/02/2020 at 20:17, soldave said:

The question is: when should I start using the motor drive in my stargazing? Do you think with my newness to it all it should come in much later and I should first get used to using it manually, or do you think it should be a used from early on.

The motor on the 130M is simple to use. Once you've found the target, you just have to lower the lever to engage the clutch & then remember to raise it again before moving on to the next one. As @Stu says, it will help keep objects in view for longer & you just need to get the mount roughly polar aligned. (I used to aim to get Polaris in the centre of view for that).

With the motor, objects will still drift out of the field of view - but it is definitely worth using it. Also you may find that you have to double check that the cogs actually engage. (I found that the spring mechanism didn't work too well after about a year of use).

Rechargeable batteries used to last for about two hours viewing, but the manual's advice to push all four buttons at once was wrong!

Cheers
Ivor

Lo-Res snaps of the Double Cluster in Perseus from last night. Fairly roughly processed in Pixinsight & approx 1 hour integration time with a Skywatcher 130pds & EQ6.

The wind was a bit touch and go, but I mainly wanted to see if I could get better polar alignment using our newly acquired iOptron iPolar gizmo... which worked... I also wanted to try controlling the DLSR (a Canon EOS600D) from the laptop... which didn't play ball on the night.

I think the oval stars are mostly caused by mount tracking/backlash. PEC (Periodic Error Checking) & adding a guidescope are next on the agenda!

Cheers,
Ivor
PS: Couldn't decide on whether to post the lo-res crop or lo-res full image..

I've found that Pixinsight can stack sets of subs which DSS (on it's default settings) rejects, particularly when my stars are egg-shaped. The results of one of my early nights imaging were badly out of focus, but I still managed to get something out of it by using PI's Dynamic Alignment tool, which meant manually selecting the stars to align on. A bit tedious, but at least the evening wasn't completely wasted!

Cheers
Ivor

The Leeds Astronomical Society have a Ross telescope which was obtained in 1859 when the soc. founded. It's said that Sir John Herschel had some involvement in it's procurement.

Here's a couple of recent pictures of it from last year around the time of the club's 160th anniversary (on a more modern mount!)

Having a star atlas like Sky & Telescope's Pocket book, or an program like Stellarium can help learn which stars are where... I often check on Stellarium which stars are likely to be visible from the back garden before starting to set up. As @Ouroboros says - using the finderscope helps to roughly locate the alignmnet stars first is a great help too.

You can also get an eyepiece with an illuminated reticule too if you wish, to ensure you get the alignment-star in the centre of the field of view.

Cheers
Ivor

We started out with a SW 130M, a close relative, about 16 months ago. It's a decent scope for a beginner and I found the best upgrades to be replacing the red dot finder with a telrad & adding a 9x50 right angled finderscope.

A neutral density filter proved useful for viewing the moon & a light pollution filter too... also a star atlas book - eg the pocket one produced by Sky & Telescope.

We've subsequently upgraded to a much more expensive GoTo but I regret selling the 130M...

PS: At higher magnifications (whether via a barlow or shorter focus eyepiece) you'll find that it's harder to get good focus & targets will drift out of the field of view much quicker...

Cheers
Ivor

20 minutes ago, vlaiv said:

Do you by any chance know how is it calculated? That might shed some light if it is useful and under what circumstances.

This might help:- https://pixinsight.com/doc/scripts/SubframeSelector/SubframeSelector.html#subframe_property_SNRWeight

Thanks @TerryMcK the ioptron iPolar solution looks really good! https://youtu.be/4MXjN34Om_g

I have an AZ-EQ6 GT Pro & find the polar scope to be very frustrating. You can change the level of illumination on the Synscan handset Utilities Menu (Polar Scope LED option) and consider getting a right angled adapter like this: https://www.firstlightoptics.com/adapters/astro-essentials-right-angled-eyepiece-for-polar-scopes.html (I made my own using a Neewer DLSR Right Angle Finder from Amazon & a plastic plumbing end cap, which works after a fashion).

I still find it very difficult to get a good polar alignment, but once I think I've got it & have done a 2-star alignment, I fine tune it using the procedure in section 11.3 of the Synscan manual ("Polar Alignmeent without Polar Scope"), where having done a 2-star align you press "Menu" & then "Alignment\Polar Alignment" & follow the prompts to fine tune the altitude & azimuth on the mount.

I agree that having to rotate the RA in order to orientate the polar reticule is very awkward... I think that's where I get most of the error... but once you've got it close & have gone through the 2-star align & fine tuned the alignment as above, you should be ok.

I've not had any problems with the Azimuth bolts - remember you have to slacken one off before you can adjust the other... There's no need to loosen the central bolt!

Regarding the setting of the Altitude to 51 deg... I think that will only give you an approximate starting position & hence the need to use the polar scope. It will also vary a bit, if you haven't got the tripod level to begin with.

To make sure I'm aligning on Polaris, I've sometimes resorted to fitting my scope / finderscope & telrad on the mount, so I could be sure I was aligning to Polaris & not some other star...

You will also need to check (preferably in the daytime) whether the polar scope reticle is aligned ok, using something like a distant aerial to check position (as per section 3.4 of the Mount manual).

Cheers
Ivor

14 minutes ago, Nigella Bryant said:

How old is that information

From "Introductory Astronomy & Astrophysics" 4th edition - Zeilik+Gregory - (p. 284) - I think published 1998 but Fig. refers to 1982/3.

Apparently Betelgeuse comprises of three stars...
(Sorry it's not a good scan)

Welcome to the forum!

I'd suggest downloading a copy of the free Stellarium software. Try looking for the Orion Nebula (M42), Andromeda galaxy (M31) & the Double Cluster... Don't expect to see as much detail as folks get with taking pictures though.

I also find a pair of binoculars (10x50 or 8x42) & a pocket sky atlas useful too...

Cheers
Ivor

So far my 'go to' reads have been:

• Patrick Moore's Astronomy (Teach Yourself series)
• Wonders of the Solar System and the Universe - Brian Cox
• Mathematics of Astronomy (Student's Guide) - Daniel Fleisch & Julia Kregenow
• Astronomy - A Physical Perspective - Marc L. Kutner

Cheers
Ivor

Hope this Press Release doesn't break SGL rules! (Mods please delete if so)
Cheers
Ivor

****************************************************

News Release from Andrew Griffith MP 

Immediate   

Thursday 30th January 2020 

‘Dark Skies’ Parliamentary Group launched

MPs and Peers have launched a new All-Party Parliamentary Group for Dark Skies in the Houses of Parliament to bring attention to increasing light pollution and the importance of preserving the ability to see a dark sky at night.

The group was launched by Co-Chair Andrew Griffith, MP for Arundel & South Downs and will also be Co-Chaired by Lord Martin Rees of Ludlow, the Astronomer Royal and former President of the Royal Astronomical Society. 

The inaugural meeting took place this week and set out the purpose of the APPG for Dark Skies.  Its aims are to: 

Dr Lucie May Green addressed the inaugural meeting as a Guest Speaker.  Dr Green is a Professor of Physics and a Royal Society University Research Fellow based at the Mullard Space Science Laboratory, UCL’s Department of Space and Climate Physics.  She was also the first ever female presenter of the BBC programme,’The Sky at Night’ and is very active in public engagement, regularly giving public talks as well as supporting her departmental public engagement programme. 

The APPG has already gained support from Parliamentarians across the political divide with a shared interest in providing dark skies over the UK.  The UK already has four internationally accredited Dark Sky Reserves which are the Brecon Beacons National Park, Exmoor National Park, Snowdonia National Park and the South Downs National Park with Gower in the process of applying.  The first recognized Dark Sky Park is in Dumfries and Galloway. 

Andrew Griffith MP said:

“I am delighted that the campaign to preserve our Dark Skies at night and to fight unnecessary light pollution has now reached Parliament where our laws are made. 

If we are to inspire future generations about the wonders of our universe – and to recognise just how special our planet earth is – it is essential that we preserve the ability of current and future generations to see a clear night sky. 

Light pollution is 100% man-made and is easy to remedy through improved design, better enforcement of planning guidelines and innovative new technologies.” 

ENDS

For further information please contact Chris Cook on 07838 911116. 

Notes for Editors 

1.     For further information on Dr. Lucie Green see here:

http://luciegreen.com/ 

2.     For further information on Dark Sky Designations see here:
https://www.darksky.org/our-work/conservation/idsp/