Abother classic refractor...

[A McEwan]

Yep, temptation got me again! This time a Pentax J80 OTA off AB&S - but I think some of you on here will recognise it from a while ago and a previous owner...

I've had a first light looking at the Sun this morning with a full aperture Baader solar film filter and it holds focus nicely. Shows a little more false colour than my Celestron/Vixen 90mm f14.4, but then it is "only" f12.5 after all!

Focuser is very smooth but a bit tight for my tastes. I'll loosen it slightly - there are adjustment screws recessed in the top of the focuser body.

The finder is non-original but quite nice and appropriate 6x30 with a sharp cross-hair. I suspect it's an Orion UK model but can't be sure yet. If anyone knows anything about Pentax serial numbers I'd be very interested to hear how old this scope is. The body has some paint nicks - quite a few actually - but no scratches or dents. It's quite heavy too, for an 80mm scope. Feels very well made and you can see the thickness of the metal on the edge of the dew-shield (which threads into place).

The optics are not as pristine as the image suggests. There is some dust around the edges which looks like it's inside the objective. Also, you can see that one of the foil spacers is set further in than the other two. The collimatable cell will be handy, but I'll not be adjusting it until I can do a star test - maybe tonight - and try it out on Mars, Venus and the Moon. I think the lens could probably do with a clean too.... but we'll see.

Ant

[John]

Very nice Ant

Lovely proportions - including a decent length dew shield which makes a nice change

[Alkaid]

That looks really nice Ant. You going to try it on the half moon tonight, weather permitting?

[A McEwan]

Thanks! Yep, that's the plan. I aim to explore the lunar highlights tonight - if the weather holds.

[A McEwan]

A brilliant viewing with the J80 last night. I started off on Venus, where the half disc was very sharply focused and remarkable little CA was seen.

The Moon astounded me. The seeing was particularly good and every little line, rille and craterlet was razor sharp. There was some false colour, and yes it's a tad more than the 90mm f14.4, but it was really not obtrusive. The area along the Appennines, Hadley, Plato etc was littered with sharply defined features to zoom in on.

A star-test followed, on Polaris, at 200x. A tight airy disc and single full diffraction ring in focus - beautiful! Mars showed considerable detail too, but I was on an alt-az mount so didn't really look at it for too long. I did think to myself though that it seemed to outperform my old ED80 on Mars, last time I looked, but that's going by memory which could be subjective of course.

Overall I'm really pleased with this scope. There are a couple of things I want to do to it, but if is a great performer.

Ant