Jump to content

SkySurveyBanner.jpg.21855908fce40597655603b6c9af720d.jpg

First Light with SkyWatcher FlexTube 250P Dobsonian


elliot

Recommended Posts

It's taken nearly three months for the the SkyWatcher FlexTube 250P Dob to arrive. It seems the whole of Europe ran out and we needed to wait for a shipment from China. First Light Optics were excellent and kept me up to date with the progress, I was even told exactly when it was on a shipping container so I could worry about it out at sea. Assembling the scope is pretty straight forward and comes with all the tools required.

The first upgrade was to replace the supplied straight through finder with a right-angle correct image finder and to attach my Telrad with a 2" riser. I'd ordered BST StarGuider 8mm and the StarGuider 2x Barlow. I figured those plus the surprisingly good stock 25mm and 10mm Plössl eyepieces should do me for now. Once the finders and eyepiece were in place, I found the scope to be quite top heavy and I need to make good use of the friction handles to keep it in place. I'll be adding weights and magnets to improve the balance. I used a cheapo laser collimator and did rough finder alignment using a distant pylon. 

Before first light, my son was looking at the scope and decided it needed a name. He came up with "Larry", so Larry SkyWatcher it is.

Sunday. 2017-7-17

Sunset 21:45. Lunar: 22 days old 56° Waning Gibbous
"Larry". F=1200, D=254.

22.30. Jupiter.  EP: 8mm. Seeing: 2-3/5, Transparency: Too early to tell

I'd left the scope out all afternoon sat by it in a garden chair  waiting for it to get dark. I'd planned for my first target to be Polaris to further line up the finders however sitting out in the garden, something big and bright in the west appeared first, so Jupiter was the target of first light with Larry. 

Jupiter was a bit low at only about 15˚ and there was quite a bit of muck. No GRS and all a bit fuzzy but I could make out 2 or 3 layers of cloud. At low horizon the mis-balance of the scope really showed itself and I had to have the friction grips set to "gorilla" to stop the big end sinking. I could see two moons to the West and one to the East. These turned out to be, from West to East: Calisto, Io and Europa. I could make out a feint star to the left which turned out to be HD112449. I thought it may have been Calisto as I could only see the 3 moons but it turns out Ganymede was transiting. I sketched a picture but I'm not showing you that. 

22:45. Polaris. Alignment and collimation

Now I could align my finders correctly - it looks like I'd done a pretty good job with the electricity pylon and everything was nearly dead on. I put the 8mm in a 2x Barlow for star collimation and again, it seems I'd done pretty well with the laser collimation as I was show steady concentric circles when slightly defocussed. This is the first time I'd done a star collimation check.
 

23:30.  M51, "Whirlpool Galaxy". EP: 8mm. Transparency: 5. Seeing: 4

I thought Rosse's Nebula would be good start as I'd recently visited the Leviathan of Parsonstown, the 170 year old 72" telescope that Lord Rosse use to first identify spiral structures in galaxies.  It was very feint to me and I wasn't sure I was even seeing M51, it may have been too early in the night and it's pretty light in the north. I'm not brilliant at star hopping yet. I intend to get brilliant at it. Also the neighbour still had there conservatory lights on so nothing was quite dark. I decided I'd point the scope at the darker sky in the south...

00:00. M27 "Dumbbell Nebula". EP: 25mm. Transparency: 5. Seeing: 4 

Using Alberio as a starting point, I hopped to Vul 13 and then straight to an easy-find M27. At first sight it does look a lot like a dumbbell but further averted vision observations revealed its fainter circular structure. Greenish in colour. (Is everything green?)

Side note:  At this point I dropped my head torch which broke into bits and I let go of the scope sending the top end slamming down on the bench. I really need to get that balance sorted!

00:30. M57 "Ring Nebula"  EP: 25mm. Transparency: 3-4. Seeing: 3

At first I thought the edge of the stock 25mm had rubbish clarity but of course it turned out to be M57 and not an out of focus star. A mate on the train two days later told me he did exactly the same thing. M57 seems oval and greenish with a non-uniform brightness edge. I was unable to make out the core star. A bunch of Mag 10 stars visible in the field of view.

00:45. M51 (2)

Back to the Whirlpool for another go and I able to make out the two sections of the converging galaxies. I'm looking forward to seeing this in a good dark sky and I'll try to describe what I'm seeing better. This observation reporting lark will take practice.

00:55. M13 "Hercules Cluster"

To finish off the night I went to an old binocular favourite. A real wow moment in my new scope. I've only used binoculars and a frankly not very good 130EQ and I was blown away. What a super pretty thing. This turned out to be an excellent end to pretty successful first light but alas with work only a few hours away, bed called.

 

 

 

Link to comment
Share on other sites

Nice report of first light with Larry... you had some good views, and yes everything in deep space is greenish or grey... Still better than a color photo IMHO, because its alive with twinkle, which to has something over a photograph.

Clear skies.

 

Link to comment
Share on other sites

Good report .Your quote of , I found the scope to be quite top heavy , and I need to make good use of the friction handles to keep it in place. I'll be adding weights and magnets to improve the balance. 

Did not realise there was a balance problem with Dobs. So you have to put weights on the back end to balance them. Interesting !!.  

Link to comment
Share on other sites

4 hours ago, cotterless45 said:

I use a taxi style roof magnet

I very nearly went for a taxi magnet but thought 10Kg pull would be overkill. I've got a healthy colleague bringing in his old ankle weights tomorrow which I shall modify to become magnetic. :)

Link to comment
Share on other sites

6 hours ago, Grotemobile said:

Did not realise there was a balance problem with Dobs.

I am a bit surprised tbh. I'm going to swap out the RACI with the original and take off the telrad just to see how much a problem it is "out of the box"

Link to comment
Share on other sites

The RACI is only 10g heavier than the straight through.  I made it balance perfectly when there wasn't any finders or EPs and I stuck 4 60mm ring magnets on the back!  Pretty sure I'm going to need those EPs and finders though :D

Link to comment
Share on other sites

Some fantastic targets for a first light. 

I enjoyed the read and when the skies do finally go dark the objects will just pop and the amount of detail you can pull out is fantastic.

The season for me is a month away still but I may sneak a few views over the coming weeks :headbang:

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.