chiltonstar

...although some of these may have confused the nearby star SAO 305 with Polaris's partner - it's only 1/2 degree or so from Polaris. I have even seen the same thing on this forum... Chris

It's quite a wide double (18 arcsec) so using the normal rule, any magnification above x10 or so would theoretically be sufficient, but obviously the real issue here is the faintness of the secondary. For me, if I can't see it because of the conditions, then the magnification I'm using is probably irrelevant?? Certainly at x60 with my 180 Mak (the lowest practical mag for me with this scope), it's easily visible under good conditions. Chris

I think tube rings would be a good idea in the sense that things would feel 100% secure, and rotation would be useful to get the finder away from the head a bit particularly when I use the scope on my EQ mount, but would add more weight. Fouling? No problems - the 2" diagonal supplied clears the focuser by about 10mm. Balancing is fine on the end position of the SkyTee; if the tube is approximately balanced (which seems to work ok with my EPs and finders given the long dovetail on the Mak), then you can nudge to position like a dob almost and it holds position, thanks maybe to the SW viscous grease. Chris

The RDF to arrive roughly where I want to go, and the RACI to locate exactly. I sometimes use the EDS80 instead of the RACI, but of course the image is not correct orientation, which I struggle with. The RDF is a metal gunsight type - it stays aligned very well compared with the SW variety. Chris

As you can see, I'm a Nikon-man! Chris

To wake the thread up again after a bit of Summer holiday........... My current doubles set-up. 180 Mak with an ED80 on a SkyTee2 mount:- Chris

It might be a best seller........can I pre-order a copy? Chris

I'm impressed you can split Lambda Cyg with 130mm John at 0.92 arcsec (?). With my 127 Mak, it takes a blue filter to split the pair (smaller Airy disk) although with my 180mm Mak, it is relatively easy to get the "dark line". Chris

Electric blue-green with the ED80, faded lilac with Mak 180. Chris

You're right Stu - quite blue. My little ED80 can do it, so your FC100 should manage! I don't think it is a resolution/aperture issue, just getting the seeing good enough for a horizon-grazing star to see the secondary. Chris

Wonderful stuff John. Obviously quite a scope! Delta Cygni is quite a challenge, isn't it? I managed a split two nights ago with seeing 4/5, but 5/5 would have been better. Antares gets easier the more often you split it, I think; the colour contrast is really impressive, even in a small scope but I wonder whether the companion is really blue or if it's just the colour contrast with the primary. Chris

Very nice image John! It's a lovely pair to see visually, even though it's very difficult from these northern skies because it barely rises above the horizon. Chris

I've just had a try with my 180 Mak. At x225, it's visible as two disks very close together, but the seeing here needs to be a bit better for this one I think (at the mo, it's about 2 to 3/5). Good luck! Chris

Nice report! 7 Tau is marked as 0.8 arcsec separation in the 2nd Ed of CDSA, making it a minimum 150mm aperture pair - one to look at though. Thanks for flagging it up.... Chris

This is the one I've seen - different from the macro adaptor you may be talking about?? http://srb-photographic.co.uk/nikon-to-m42-lens-adaptor-6050-p.asp Chris

£22 apparently......I'm not sure about the lens element, they appear not to have in the image on the website. Chris

I've recently upgraded to a Nikon D750 (from a D300), and I have to say the high ISO performance is very impressive, with very decent images up to ISO 1600 or so before colour noise starts to be visible. The standard SRB adaptors for M42 lenses to Nikon do maintain infinity focus, according to SRB, although I'm unlikely to use one as some of my Nikon manual and auto lenses are sharper than any M42 lenses I've tried! The WiFi connection to my Samsung 7" tablet (Android) seems to work well, and I've plans to use it soon for Moon imaging. Chris

The objective was made by Vixen and was sold for a time in the UK before they switched to a shorter fl. I agree, F13 is a good compromise, good detail, cheaper EPs and still (just about) manageable on an EQ mount! Chris

Talking of anti-aircraft missiles, my first ever frac - ca 1983, home made OTA, still in use! It's an f13 102mm achromat and still (last night!) gives gorgeous views of planets and doubles. Last night's views of delta Cygni and Saturn were still impressive, with a beautiful rendition of the peachy-cream colour of Saturn and its rings. Chris

Pic below. Essentially, I removed the base from the RDF and attached it with two macho nylon cable ties. It's tight/loose enough I can rotate it to refocus the RACI if I need to. To align, I pointed the RACI at a brightish star, centred it, and then adjusted the RDF until it covered the star. In use, I swing the scope using a rough aim with the RDF, and then use the RACI. Chris

Perhaps just better seeing, with a field in front of me - the fact that the split shows up well in an image shows it's not just eyeball factor? Chris

Nice! And with all that frackery, you still can't split Zeta Her? Chris

My mini (grab 'n go) frac set-up. One day I hope it will grow up and acquire some more inches round its waist..... Chris

With all these wonderful fracs, we should organise a FracFest somewhere.... Chris

Yes, easily do-able. A gem. Chris