Skyliner 300P Dob

[johninderby]

Skyliner 300P Dob

Just picked this up last week and couldn't avoid making a few mods. It's a good scope just as it comes, but with a few hours work it's turned into something that far exceeds my expectations. I didn't spend very much extra as I used some equipment and parts that I already had, and the only real expense was the new focuser. I sold the stock focuser and finder on eBay for £75.00.

First job was to add some flocking to the tube. I had enough on hand to do about a foot at either end. I also removed the spider and secondary mirror and sprayed the vanes and back of the mirror with Ultra Matt Black paint, not forgetting to paint the ends of the chrome nuts that protrude into the tube and the inside of the trim ring on the end of the tube. Together with the Astro Engineering Dark-Cap shield this really increases contrast. Unfortunately A&E print a ghastly looking huge white logo on the outside of the cap, but some black sticky back plastic film covered that up nicely.

The focuser is the new Antares dual speed that is the same as the latest Skywatcher. Very nice anodised black finish and is very, very smooth. Fitting wasn't too difficult after new mounting holes were drilled. The stock focuser mounting plate is square but the Antares one is a bit narrower and doesn't quite cover the hole in the tube at the sides, so I made up two small black plates (aprox 10mm by 80mm) that bolt through the original mounting holes and can just be seen in the photo. The standard single speed crayford focuser that comes with the scope isn't that bad, not the best looking one around, but works quite smoothly.

Next was an APM 60mm right angle finder with rotating back and a 70 degree widefield illuminated eyepiece. Took it off my SCT as I didn't really need it on a GOTO scope, and I had a spare 50mm finder anyway to put in it's place anyway. I added a laser finder as well as I find that this is the perfect combination on a dob.

I fitted a small grab handle near the focuser and also a long rubber covered carrying handle about halfway down the tube. Makes it so easy to carry the OTA upright now through doorways with one hand on the grab handle and the other on the carry handle. Feels nice and secure as well, and you can lower the OTA into place gently without knocking the mirror out of alignment. They are also perfectly positioned to place your hands on while guiding the scope.

Finally I fitted some 5 inch locking castors that had been sitting under my workbench for a couple of years, a cooling fan and a Manfroto quick release unit to the bottom of the tube that holds the balance weights but can be removed in seconds if needed.

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Overall the setup works perfectly and does exactly what I want. After having observed with it a few times now two of the most useful mods have turned out to be the castors and the handles.

John

[mcut]

v nice

[Macavity]

Very handsome! Always seems the little (Nay - skilful, well executed etc.)

mods that transform the "ordinary" into something Personal and Special.

[Xunil]

That's some great work and inspiring too - I've just got a 250px myself.

What did you use to flock the inside?

Is there a risk that the material can flake off over time and get the primary dirty?

[johninderby]

Hi

Bought the flocking material a few years ago, and I can't remember erxactly where I got it from. It was a place that specialised in display stands and supplies for exhibitions.

It is self adhesive (understatement !!!) and once put in place it just won't come off. In fact if you want to remove it you'll need a paint scaper and some solvent to get rid of all of it. There doesn't seem to be any loose bits coming off the flocking so far, but if it does I will give it a light spray of the Ultra Matt Black paint to seal it down.

There's a good item on CloudyNights on flocking:

http://www.cloudynights.com/item.php?item_id=805

John

[Xunil]

Thanks for the link John - it's even done with the 8" version of my scope.

This will be my first mod for sure.

[SteelRat]

Like it John 8) Great looking scope.

Cheers

Matthew(SR)

[Sam]

Very nice scope and well done on the mods!

[rob7]

I'M JEALOUS!! Lovely mods John and funny enough most of your mods are what I've been pondering to do since I bought my 300P some 2 months back. The castors have been located, but not purchased. Handles would be very beneficial but I haven't looked for some yet. The shield, again just needs me to put my hands in my wallet. At the mo all I've added is a telrad finder, Wixey digital guage and I happen to already have a Antares dual speed focuser which I've had as long as I've had the scope but still haven't fitted it yet! Which brings me to a couple of questions. As you know the Antares isn't a simple direct replacement for the Skywatcher jobby and thats partly why I haven't tried to adapt mine to fit the 300p. Would you say now your using the Antares on the 300p, that it is a definite improvement over the original focuser and do you have any problems reaching focus with any of your eyepieces ? [Antares focuser has a somewhat lower profile to the Skywatcher focuser]. Would love to use the Antares as its certainly 'prettier' than the Skywatcher effort...

P.S. Have you any more ideas in the pipeline for your dob?

Rob.

[johninderby]

Fitting the new focuser wasn't that hard. Just drill 4 new mounting holes for the new base. The hole in the tube is bigger than it should be and isn't quite covered at the sides by the new base which is narrower than the original. I just made two small plates about 10mm by 80mm and fastened them into the original mounting holes and this covers the gap nicely. In my photo you can just see one of the little black plates peeking out at the side of the new base.

(click to enlarge)

I never used the original focuser which seemed to work smoothly enough, but playing with them side by side on the workbench the Antares felt so much more solid and precise. The 10:1 fine focus also has one additional major advantage, as it only requires the lightest touch so there's virtually no vibration while focusing.

More infocus than I needed with any eyepiece. Needed a few mm extra outfocus travel with some eyepieces, but now use a parfocal ring under the 1.25" to 2" adaptor to give that extra bit of travel and have removed the 1.25" extender.

Put some carry handles on the base today to make it easier to carry outside. Have to wire up the cooling fan properly tomorrow, just temporarily rigged at the moment. Bought a little computer fan electronic speed controler (£5.00) that works a treat and lets you set the fan speed to whatever you want. Don't know why no one else seems to have used one of these little controllers yet, they are cheap enough.

Regards

John

[rob7]

You've helped me stop me lazy and get me off my backside! Just bought some 4" castors of evil bay. [mind you, I did do this sitting down!!!] Going to offer up my Antares focuser to my 300p tomoz.. Another question though is why you have added the balance weights to the ota? I had balance issues with my previous Revelation 12" dob and was going to add magnets, but now I have this 300P and its tensioner handle I find that I get good balance and tension what ever I've mounted on the ota [50mm finder, Telrad, Meade 2" telextender barlow stacked onto a Revelation 2" ed barlow and the topped with a Meade 2" 40mm ep for example]. Thats quite some weight which would have the Rev dob 'diving' head first in no time. Not so with the 300P.

Cheers, Rob.

[Astronut]

Interesting mods - may copy some if that's ok with you although I was thinking of getting a Moonlite dual speed focusser. I especially like the tube carry handles as I find the tube a little awkward to move through 2 doorways and they'll make it much easier to put in the back of the car if I ever get chance and time to go to a dark site or star party.

Where did you get these handles and also what is the Astro Engineering Dark-Cap shield?

[johninderby]

I'm only using one balance weight of about 1 pound, which is mounted on an aluminium quick release bracket. The Antares focuser weighs about twice as much as the stock focuser and the 60mm finder weighs a couple of pounds on it's own so it really does need the balancing weight. With the weight the tube balances perfectly without any tension being applied by the handle so Alt movement is very smooth.

Got the handles from an industrial supplier WDS Ltd, not cheap but they are proper industrial quality. They do have a lot of other types of handles that are cheaper though.

http://www.wdsltd.co.uk/Handles%20and%20hinges/Handles/WDS8517%20Handle

[johninderby]

Dew cap is something new from Astro Engineering.

http://www.astro-engineering.com/new_products.php cap is new from Astro Engineering

[Andrew*]

Nice scope and very nice mods - I bet it's a great pleasure to use now.

This post has triggered me into buying some flocking felt to do my 8" newt - cheers!!

Andrew

[tom.yates]

LOOKS SUPERB

[jgs001]

Very nice looking gear there John

[Astronut]

I've been doing a bit of reading on flocking after seeing this and it seems like a worthwhile mod. I see alot of people have been using rolls of self-adhesive felt from places like hobbycraft and homecraft but the proper stuff (Protostar flocking paper or this stuff) seems to be only available over the pond. I'm a little reluctant to use felt as I think it's not waterproof and it might attract alot of dust bunnies and shed fibres onto the mirror.

What material did you use and are my concerns over felt unfounded?

[johninderby]

As I explained in an earlier post I bought the flocking material a few years ago. It is a commercial grade and as far as I can tell it is made from an acrylic fiber so it won't absorb moisture and the self adhesive backing is industrial strength. It sticks instantly to anything and is almost non-removeable (if you apply it in the wromg place it takes a paint scraper and solvent to remove it) and so has to be applied very carefully.

Felt does absorb moisture and isn't physicaly very strong (sheds easily) so I am very dubious about using it.

I wish I could remember where it got it from, but you might try commercial suppliers of display stands and exhibition materials.

[Astronut]

I notice you've only flocked the bottom and top half of the tubes and I see this is a popular approach. The area opposite the focusser is especially important. Is there any advantage optically to flocking the whole tube?

[johninderby]

Hi

That's all the flocking that I had or I would have done the whole tube. However from what I have read doing just the ends gives about 90% or more of the benefit of doing the whole thing. The stray light that reflects up around the primary mirror can wash out contrast almost as much as that going into the focuser, so it's just as important to do that end as well as the focuser end.

[Astronut]

I think I'll do the whole tube then - may as well I'm going to get a new focusser first and a couple of those handles while I'm at it.

I'm going to order some of this stuff from ScopeStuff - seems to get good reviews and the price is good but the shipping costs from the States might be a bit more. Looks like I'll need 2 large rolls at least (+ 1 small roll?) but I'll have to do some measurements first.

[themos]

I'm holding out for some FLO flocking material. Hint, hint.

[Xunil]

There's a list of dealers for the Protostar stuff:

http://www.kendrickastro.com/astro/dealers.html#England

None of them have the flocking paper on their sites though from what I can see.

[FLO]

I'm holding out for some FLO flocking material. Hint, hint.

Am still speaking with manufacturers/suppliers but am confident that we will find a suitable product.

I'll send you some to test when we do.