Captain Scarlet

NGC 1999. Stolen for my list, thank you. A fascinating (non-)object. Which list I’ve been compiling since mid November for my “next” session, which the weather has not yet allowed!

1 light-second away now 😮 

Perhaps just a tiny little stretch to a companion 12” why not? 😃

So satisfying bang on projections.

What were the flakes floating around just after telescope separation? Carbon Dioxide?

3 hours ago, JeremyS said:

Very nice Dave.

I see you went for the optional accessory those Pentax guys offer. Nice handle!

Excuse me I need to point this out. That is not a handle. These are handles:

Interesting. My one is not far from yours in the production run: yours is No 048, mine is 026.

15 minutes ago, ONIKKINEN said:

… Takes a special kind of crazy to do astronomy in Finland it seems …

Luckily, being Suomalainen, you are a perfect fit! 😁

full disclosure: I am half Finn myself 🇫🇮 

It seems as though my current weather, in SW Ireland, has been exactly the same for weeks: 10-15mph SE avg gusting to 20-25mph and solid low cloud, day in day out. And before that when there were clear spells, it was positively stormy. So anything other than a grabngo or bins hasn’t been out for a couple of months. 

Another vote for Kowa. I have a tsn-883 and love it. 510mm FL and 88mm aperture. Kowa also supply an adapter to allow 1.25” eyepieces, shown here. It quite happily takes 150x mag. Though swapping eyepieces is a bit of a faff, you have to unscrew and loosen some hidden Allen-grubs, as opposed to the native bayonet-fitting for their own eyepieces (which are also very good).

Magnus

6 minutes ago, vlaiv said:

Actually - I'm talking visual only - hence all that mentioning of eyepieces and field stops

fair enough - I should learn to read

Are you talking AP only? If so, how would, say, a Canon 400mm f/2.8 fare? The early non-IS ones can be got quite reasonably, I think, although they are very heavy. 400/2.8 = 143mm aperture?

M

I assume it's cloudy in Novi Sad?

20 hours ago, John said:

Agreed - highly impractical. Imagine where that eyepiece would be observing Jupiter and Saturn from the UK ? - "ladder time"

In my case I would also need to explain to my neighbour why half the length my scope was hanging over his garden

 

… or maybe he wouldn’t wait for the explanation and would simply prune it as would be his right 😄😄

I have 3 Maks, a skymax 180, a skymax 150 and an Intes M603 (150mm).

Whilst I agree with @Nik271 that once collimated, the skymax line are unlikely to need collimating again, if one does need collimating, the mechanism skywatcher provide for these scopes is crude and not especially easy: 3 pairs of “push-pull” threaded bolts at the back for the primary only.

Other Maks, such as my Intes (which is a Rumak-Mak) can be much more difficult owing to adjustable primary AND secondary. In certain circumstances they can be impossible to collimate, where for instance the primary has been seated tilted relative to the focuser, which might also be the case in a bad example of an SCT or CC with unadjustable fixed primary mirrors.

If that focus-tube-vs-primary-axis tilt is not adjustable, which most small ones are not as I understand it, and it's out, you’re in trouble from the start. With mine, that was indeed “out” when I got it, there was no native adjustment mechanism, so I had to shim the primary on its seat around the baffle-tube before even starting on the 6 collimation-adjustments proper.

So collimation can be a problem with Cats, and can get horrible sometimes. A situation you’ll rarely get with refractors.

Cheers, Magnus

Yes lovely picture. Last night was due clear and at 7pm it was indeed, so I took the Intes out to cool. When I went out a bit later it was blanket cloud and stayed that way. Haven’t been out with anything but bins for 7-8 weeks now.

M

I’ve just read the Wikipedia article on JWST. A review in 2018 revealed 344 single-point failures, any one of which could doom the whole. Which means that if they are all independent, each one has to be reduced to an average 0.2% chance of failure (1 in 500) just to achieve a 50% chance of none of them failing.

Looked at another way, if each one has a 99% chance of success, 1 in 100 of failure, the chance of none of them failing reduces to a bit over 3%.

On that view, I have to say I’m more pessimistic 😟 . I sincerely hope they’ve mitigated them all 🤞.

52 minutes ago, Stu said:

Turkey roast served at desks I guess this year?

No chance. Can’t let pursuit of an expensive hobby get in the way of something as important as Christmas Dinner!

1 hour ago, malc-c said:

Well the replacement secondary  (larger than the stock 200P) came from Orion Optics and was fully coated (unlike both offerings form OVL (Skywatcher).  And seeing that the OP has an Orion Optics VX8 would assume that his secondary is fully coated.  If it is then this would suggest to me that having ruled out an unsilvered mirror, then collimation is the issue, including bent or mis-aligned spider veins.  If the scope is fairly new it might be worth the OP contacting the retailer (or if purchased direct - Orion Optics) for advice and what options there are to return the scope for inspection and repair if found faulty.

I too have an OO VX8, unfortunately I don’t have immediate access to it and I didn’t check it when I was last near it. I shall check it as soon as we meet again.

M

Almost every Newtonian secondary mirror I have ever seen has a short section of straight edge in the silvering where the mirror has been grasped by a holder during the silvering process. That will produce a spike.

M

Haha we’ve all been there, glad no serious damage. I tried attaching a scope to my then quite-new az-eq6 without realizing I’d forgotten to bolt the mount to the tripod. I pushed it off the tripod 😱😱 luckily mainly onto grass not my foot.

3 minutes ago, wulfrun said:

Latin has the distinction of being my only exam failure (at O-level) so I stand corrected. I have found what Latin I managed to absorb to be useful at times but clearly it ain't up to snuff here!

Haha I’m only drawing on my O-level too so highly unreliable also 😁😁. I did get an A and to this day I have no idea how. I was rubbish at it, hated it, and found the exam very difficult. I think they must’ve got some papers mixed up!

4 minutes ago, wulfrun said:

"Morpheus" might sound like it's latin-derived and hence pluralised as "morphei". However, it's not, it's a made-up name based on a Greek root. As such, since it ends in "s", the plural ought to be made by adding "es" for "morpheuses".

If Latin it’d depend whether it was 2nd declension or 4th declension, in which case the plurals would be Morpheii or Morpheus respectively. If Greek, I have no idea 😃

… the things one remembers from 45 years ago 🙄

5 hours ago, Stu said:

This was my longest scope; OO 300mm f6 which was a bit of a beast. For context, the scope beside it is an 8” f20 Mak (OMC200). It wasn’t very stable on the AYODigi II, much better on a dob mount. Anything longer much be completely insane! ...

Haha that is more ridiculous than my SW 300p plus Skymax180 on an az-eq6! Was it a usable set-up?

M

Wow good for you Joe! A number of us have had their dark-sky Epiphany moments while exiting the pub, myself included and @niallk from memory. A common theme seems to be "where have all the constellations gone?". I recall someone else saying looking up was almost vertigo-inducing, looking up you felt as though you could fall into the sky.

I had a quick check to see actually what your sky would look like from Mount Magnet. Orion completely upside-down, he must have a serious permanent headache ! And M42 more than 50 degrees up! I also learned that Western Australia (all Australia?) abolished daylight savings a few years ago.

Cheers, Magnus

If it’s not a sunny day, I’ve used this method to roughly measure focal length.

Carefully set the mirror up on on its side on, say, a kitchen surface. Obviously in such a way that it can’t fall flat or roll off 😱

Get a piece of board about the same height as the mirror, and drill a 2-3 mm hole approximately in its centre.

Arrange the board vertically with a bright LED torch behind the hole. Adjust the distance of the board from the mirror until the reflection of the lit-up hole back onto the board is in best focus.

Measure that distance, which is known as the centre of curvature, and halve it to get the approximate focal length. The beauty of it is too that any error you make in the measurement is halved as well.

M