John
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Posts posted by John
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Going to Arizona late Summer. Hoping to take a small scope or large binoculars. Some dark skies in the region that we are visiting apparently. Planning to visit the Lowell Observatory and Meteor Crater too
Not getting too excited though - we spent a month in Australia last year and only had a couple of clear nights the whole time we were there !
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"Astro corner" - I have a couple of those around the house
Lovely setup Piero - looks super in that "natural wood" finish
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It will be interesting to see how the 8 inch F/8 compares with the Tak 210 Mewlon in performance. Might be a close run thing ?
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In the words of Hawkwind, "Hurry on sundown, see what tomorrow brings"
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This surface brightness vs concentrated / integrated brightness thing is worth getting your head around. There are many deep sky objects which turn out to be a lot harder to see than you think they ought to be, especially if there is some light pollution about, because they are extended objects and their actual surface brightness is a lot lower than the integrated figure that is given for them. Messier 33, the Triangulum Galaxy is a good example. It's listed as magnitude 5.7 but it's face on and an extended object with a surface magnitude a lot lower so it's easy to miss it altogether and be scratching your head over why you can't see an "easy" mag 5 object.
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The Veil is big, very big. You will need to do it one segment at a time with the 12 inch dob at your lowest power. The Eastern Veil is the brighter segment:
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1 minute ago, MSammon said:
Yep just found the ring nebula! It was more distinct than the dumbbell nebula to me. At the moment I am stuck on high power. Need that longer focus tube for my two inch eyepieces. Will have a look for the veil nebula. Thanks. I have a UHC filter but it’s 2”. Will have to get more.
You can use a 2 inch filter with 1.25 inch eyepieces - it should screw onto the 2 inch eyepiece adapter. Just be careful that the 1.25" eyepiece barrel does not extend down so far that it touches the filter.
A UHC filter does help with the Veil and quite a lot of other nebulae. An O-III is the Veil filter though, IMHO.
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Nothing nebula-wise really is as bright and extensive as the Orion Nebula. M27 is usually good from my skies which are around Bortle 5 I think. A UHC filter makes it "pop" a bit more especially in the smaller apertures and shows more structure.
When you start looking for M57, bear in mind that while it's brighter than M27, it's a lot smaller.
The best Summer nebula and probably my favourite Summer DSO is the Veil Nebula. It's faint without a filter, even with a 12 inch scope but, wow, with an O-III filter it's a wonderful, complex and many faceted object. Very big as well !
(sorry thats another expense - an O-III filter !)
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2 hours ago, Tubby Bear said:
They also have the less expensive alternative:
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14 hours ago, MSammon said:
Can anybody tell me which crater this is by the way please?
It's Copernicus. I got it myself a little while back with my Tak 100 and my old Samsung mobile:
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21 minutes ago, Alan White said:
I should think from the picture that the OOUK ones are just cut from an alloy tube.
No, they are made of steel. No flex in them at all.
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1 hour ago, Rob said:
Very nice Stu. Makes me miss my OO SPX 8 f6 even more.. nice to see they have not changed the lens cell!!.. Oh and swapped the focuser out on mine, had to re-size the hole for that. regret parting with - oh yes!
Just like a slightly smaller version of my 12 inch F/5.3 SPX Rob. Those curved secondary supports are quite disctinctive !
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Less power usually makes things crisper. I always prefer a smaller scale sharp view to a larger scale mushy one. There are some exceptions to this, usually when I'm searching for a very faint point source such as a supernova or one of the fainter planetary moons.
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You could try less magnification - 450x is a heck of a lot even on the moon and only under the very best seeing conditions and with the scope collimation absolutely spot on will it result in sharp views. With my 12" F/5.3 dob I often get my sharpest views of the moon at around 280x - 320x. Occasionally I can go a little further and still get a sharp view but most of the time things get softer above that sort of magnification, rather than sharper.
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1 hour ago, MSammon said:
Don’t know about the focal plane. Do you not use a Telrad or just that right angled focuser John?
I use a Rigel Quickfinder which is just this side of the RA finder - It's not a good photo !
This shows the arrangement better and the Moonlite focuser that I now have fitted:
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1 minute ago, AdeKing said:
No worries John. I don't often use the EQ5 as I prefer Alt AZ so I normally have a mini Ercole or my WO EZTouch attached to the Uni 18 as I use them more.
I'm just the same Ade.
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I would have thought that focuser and extension would have done the job, unless the focal plane on your scope is unusually far out from the tube wall ?
This was the original focuser on my 12 inch F/5.3 which worked well with a wide range of eyepieces including the Myriad 20mm. It looks a similar in proportions to your current setup:
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It's a shame that there are not more of these longer newtonians available. An 8 inch F/8 with a modest central obstruction and a decent quality mirror is likely to perform as well as a 6 inch apo refractor I reckon, and better on DSOs but for a fraction of the price.
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The UNI 18 will make a difference (I have the UNI 28). Not only is it a more stable tripod than the stock 1.75inch one, the ash wood absorbs vibrations well - thats why they make hammer handles out of it.
The UNI tripods are even better than the 2 inch steel tubed ones - I just did not realise you had one !
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The longer tube will have an impact, thats for sure. The more stuff you can add that minimises the need to touch it, the better the vibrations will be controlled.
If one comes up, the 2 inch steel tubed Celestron CG5 tripod is taller and quite a bit more sturdy than the 1.75" steel tripod. Might be worth considering. I used to use a 150mm F/8 and also a 127mm F/9.2 refractors on a CG5 (same as EQ5 really) on the 2 inch steel tripod and it did a decent job for visual observing.
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This older classic EQ mount landed here today - Vixen GP in Celestron colours. A nice alternative for my 100-120mm refractors and I'll be getting at least the RA axis driven for relaxed high power observing. I've not owned a GP for a long time and I'd forgotten a) how well made they are and b) how light they are for their capacity. Nice Japanese manufacturing
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Excellent looking scope Stu - sure to be a wonderful performer as well
I used to have a Watchouse EQ platform as well for my 12 inch - they work very well. Pity that the company does not make them now.
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Is your EQ5 driven Ade ?
I've found having a driven mount makes a lot of difference to vibration handling with a long scope on board.
A sturdy tripod is impoartant as well.
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1 hour ago, Tubby Bear said:
Interesting spider design they did back then. I wonder why they discontinued it ?
It was an option that OO offered for a few years but not enough demand aparrently and it was harder to fabricate I believe.
I still get diffraction of course but it's spread evenly across the field of view. No "spikes" either side of brighter stars. They were fitted to the scope when I purchased it (used) and I've seen no reason to change them.
Martin Mobberly opted for the same pattern when he comissioned his 10 inch F/6.3 from OO:
My scope is the 12 inch F/5.3 version of his.
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Skywatcher 6mm UW eyepiece question
in Getting Started Equipment Help and Advice
Posted
The one you link to at FLO is quite a bit better quality than the 356 Astronomy one. In all honesty neither is really a UWA (Ultra Wide Angle) eyepiece though. Wide angle, maybe, or at least wider than a stock plossl or kellner type.
There was a report recently from an owner of the 4mm Skywatcher UWA planetary eyepiece thatr was very favourable.