130P-DS overall diameter

[Stub Mandrel]

As tonight looks like a clout-out for my part of the Midlands, can anyone cheer me up with the diameter of the outer rim of a 130P-DS, so I can make a bahtinov mask for one that's on its way?

I'll just cut out the plastic bit and make a foam ring to fit when the scope arrives.

[Lerxst2112]

According to http://www.teleskop-express.de/shop/product_info.php/language/en/info/p3933_Skywatcher-Explorer-130PDS---130mm-f-5-Newton---2--Crayford-Auszug.html the outer diameter is 160mm so my guess would be if you want to fit inside the tube would be to take a millimetre or two off the outer diameter for a snug fit.

Hope this helps. I quite fancy one of those myself when I can afford to upgrade.

[Stub Mandrel]

Thanks, I need to make it slightly oversize so it overlaps the foam ring which will go around the outside, but I wanted to be sure it will fit out of this bit of plastic I have go, which it should. I will make it 180mm and then trim it to suit. The actual size of the slits will be calculated by the online thingy.

[DaveS]

Just put the ruler on mine and it's 160mm.

[Stub Mandrel]

Thanks both.

[Dave In Vermont]

Every astronomy-person should have one of these critters:

https://www.amazon.com/s/?ie=UTF8&keywords=6+inch+digital+calipers&tag=googhydr-20&index=aps&hvadid=39805522547&hvpos=1t1&hvexid=&hvnetw=g&hvrand=2021167882499313519&hvpone=&hvptwo=&hvqmt=b&hvdev=c&ref=pd_sl_wm96mdonx_b

Some doubt how accurate they might be - due to their low-cost. I, too, was a doubter. But I bought one anyways. I have an extremely accurate manual one - and very expensive - so I did a side-by-side comparison. They matched. And they even come with a battery and an extra one in their very nice case. Easy to use and go all the way up to 6" - 150mm.

Enjoy!

Dave

 

 

[triton1]

I,ve got the same one well worth it.

[Stub Mandrel]

8 hours ago, Dave In Vermont said:

Every astronomy-person should have one of these critters:

https://www.amazon.com/s/?ie=UTF8&keywords=6+inch+digital+calipers&tag=googhydr-20&index=aps&hvadid=39805522547&hvpos=1t1&hvexid=&hvnetw=g&hvrand=2021167882499313519&hvpone=&hvptwo=&hvqmt=b&hvdev=c&ref=pd_sl_wm96mdonx_b

Some doubt how accurate they might be - due to their low-cost. I, too, was a doubter. But I bought one anyways. I have an extremely accurate manual one - and very expensive - so I did a side-by-side comparison. They matched. And they even come with a battery and an extra one in their very nice case. Easy to use and go all the way up to 6" - 150mm.

Enjoy!

Dave

 

 

I'm not sure whether I have five or six in my workshop... different makes different quality; sometimes the cheaper ones are better it all depends which factory the board inside comes out of. I have two I compared for their temperature stability, one drifts but the one from a discount supermarket stays rock solid! I haven't used my manual vernier caliper for about 15 years.

[Skyline]

Maybe this will help you.

http://astrojargon.net/MaskGenerator.aspx

[Stub Mandrel]

3 hours ago, Skyline said:

Maybe this will help you.

http://astrojargon.net/MaskGenerator.aspx

Thanks, I find that site irritating as despite having more image editing programs than you can shake a stick at I can't get the SVG files to print! There's another site that has PDFs generated in various sizes from the astrojagon site so what I do is print one of those off scaling it to fit (the sizes are a bit iffy) the 5" one at 110% is a good match for the 130P-DS.

I've only cut out half the mask so far (slicing endlessly through plastic hurts!) but as Vega is virtually straight up I've been able to focus on it by lying my 150PL mask on top.