SW 150 Evostar

[Din]

Just bought the Skywatcher 150 refractor. Anyone any advice on essential improvements?

I've already acquired an EP & filter set. I've read a focuser upgrade is possible but is it worth it?

Adjusting the focus does set off quite a few vibrations, I find it hard to find focus with the image shaking.

Cheers

Ed

[Brian Nordstrom]

Hi Ed , is it the f/5 of f/8 ? I have the f/8 and its a great scope for all things , luna, planetary, and deep sky .

Any chance of a photo?

Brian

[damnut]

Hi Ed,

I have the meade/ Bresser 152 mm f5 with a large petzval element. A couple of things, possibly a uhc or -v filter if you have too much ca when viewing planets / moon (blue / purple fringe around objects). A pier extension to put on the mount cos that will save your back.

If you are having vibrations when focussing, you do not say what mount you have, so you may be better advised upgrading the mount so that it is stable rather than spending on the focusser. If you have any funds left after that lot a nice widefield eyepiece ..

Hwyl!

[John]

I've owned a few of these 150mm F/8's. They are decent scopes but do need stout mounts to control vibrations due to their long tubes. I found a Celestron CG5 on it's 2" steel pipe tripod OK for visual work but an HEQ6 or better still an EQ6, would be better again. The original and older EQ5's with the aluminum tripod legs are really not up the job !.

The stock focuser can be made to work well enough if you re-grease it and tweak the tension on the rack and pinion using the grub screws on the top of the focuser. At F/8 I didn't feel the need for a duel speed focuser.

If yours has the collimatable objective lens cell then it's worth using a cheshire eyepiece to check the collimation is OK. Using a laser collimator to see if the focuser tube is square with the optical axis of the scope is worth doing too - often they are not !

These F/8's do show some noticable false colour on bright stars, the moon, Jupiter, etc but you would expect that in any F/8 achromat.

I found the standard scopes worked well enough up to around 200x (on a good night) but magnification beyond that is "empty" and does not seem to reveal any more details.

The are surprisingly good for low to medium power deep sky viewing.

You may need a pillar extension to get the eyepiece up to a comfortable working height and a right angled finder can be a boon on these scopes.

[twotter]

Has anyone tried an Evostar 150, or similar telescope, on a SkyTee?

[John]

Has anyone tried an Evostar 150, or similar telescope, on a SkyTee?

Yes, I tried a Meade AR6 on a Skytee II. It was stable enough although the dovetail clamps on the Skytee II I had were not secure enough so would need upgrading and the slow motion controls seemed a long reach from the eyepiece !

Don't want to derail the OP's thread too much though

[damnut]

Hi Twotter,

Like John have mine on Skytee, and if there is no breeze on an az4. Absolute must is the pier extension. On skytee balanced out by a russian 110mm mak built like T34.

Cheers

[twotter]

Thanks gents & apologies to the OP. Looking forward to a first light report?

[Din]

Hi again

The scope is the F8 and I have an HEQ5 mount which has the Syntrek feature. I can't put a photo on I'm afraid, still waiting for an SD card for the camera, ordered off Amazon two weeks ago.

I will look into a uhc or -v filter, though I don't know what they are yet. There is a lot of CA when looking at Jupiter. Not so bad on the moon, perhaps because I have a moon filter. Last night I tried the moon filter on Jupiter, and it got rid of the CA but made the image quite dark. I presume the other filters will do a better job by allowing more light through.

The pillar extension sounds like a good idea, it is difficult to manage with high altitude objects.

I am not sure if it has a collimatable objective lens cell. The objective lens appears to be held in place by a threaded ring and has some sort of gasket between the ring and the lens. I would guess this is a rubber ring but it feels quite solid.

I'll look at re-greasing the focuser. The factory grease seems quite sticky and may be causing some stiffness.

The 6mm EP I bought seems to have a narrow lens, I think this is because it has a narrow field of view. I find it easier to use the 10mm supplied EP though it looks poorer quality. Maybe a wide view EP as suggested....

Cheers for all your advice.

Ed

[damnut]

Hi ed,

The ep's supplied with the scope do it no justice, a step up are the BST explorers, which are great for the cost around £50 each here :-- http://www.skysthelimit.org.uk/telescope%20eyepieces.html . They have great eye relief and a large lenses whch ,make them a pleasure to use.

Then the Baader Hyperions, Celestron Xcels all around £100, after that deep pockets needed!. The filters I mentioned cut down the purple / blue ring that achromats generate round brightish objects, if you are hunting for faint fuzzies then you will not need them. They target specific frequencies of light and do not darken the image as much a moon filter would.

Best Regards

[Din]

Thank you Damian

I will look at the BST range. I'm a bit disappointed with the Celstron EP so may invest in a quality 6mm.

Ed

[twotter]

My TAL refractor is not so bad for chromatic aberration, it does show on Jupiter, less so on the Moon. Prior to using it I had been advised that a fringe killer filter might be a useful purchase...

http://www.firstlightoptics.com/achromat-semi-apo-filters/baader-fringe-killer-filter.html

I've decided I can live with the CA in my TAL, but as and when I get a bigger refractor I'd definitely consider buying one of these.

[John]

The best of the minus violet filters is the Baader Semi-Apo I believe:

http://www.firstligh...apo-filter.html

I've tried a couple of others but, while the false colour was reduced, they gave a colour cast to the images that I was not too keen on. The Baader Semi-Apo does not do this, or at least not as noticeably.

UHC filters are something different again - they enhance the contrast of nebulae. They are not designed to tackle false colour though.

The collimatable objective lens type looks like the left hand photo below, the non-collimatable type is the right hand one - you can see the different objective lens designs I hope:

[Din]

John

Looks like I have the scope on the right.

Cheers

Ed

[steve_bham]

You can regrease the focuser and use Teflon tape inside to make the movements silky smooth.

[Din]

Thanks Steve.