John

It is worth bearing in mind that the original review by Alan that kicked off this thread was posted 7 years ago. I'm sure there are many examples around of scopes and other equipment that were "king of the hill" 7 years ago that have now had their capability exceeded by more recent products.

I believe Astro Physics have used FCD100 in their latest incarnation of the Stowaway triplet ?

There is extensive data here on eyepiece specifications compiled and updated each year by Don Pensack in the USA. Don knows a lot about eyepieces !: https://www.cloudynights.com/topic/657524-2019-eyepiece-buyers-guide/?p=9288710

I call this one "Cloaked Klingon Bird of Prey with Port and Starboard lights left on by mistake"

The issue with FPL-53 at one stage seemed to be its continuing availability - there were rumours that Ohara were going to reduce or phase out it's production. But since then I've seen quite a few new scopes coming into the market which specify at least one and sometimes more FPL-53 elements and some in quite large sizes so it seems that, for now, the future supply of FPL-53 is secure. Its price though will be of concern to the manufacturer of lower priced ED refractors - As of 2017, FPL53 glass cost around 20% more than FPL-55 and nearly 100% more than FPL-51.

I have a couple of less expensive UHC filters as well as the Lumicon O-III - a Meade 4000 Nebular (spelt like that !) in 1.25 inches and the Explore Scientific UHC in 2 inches. Both do make a difference and have quite generous band pass widths so the effect is much more subtle than the O-III. Most of the time though I'm wanting the filter to give a good "kick" to the contrast of the nebulosity and the O-III is by far the best for that. This illustration of the impact of a high quality O-III filter is not an exaggeration on a darkish night:

Not wanting to question Suiter of course but I have seen a noticable improvement in the star test before and after getting the tilt of the objective lens correct. Most of my refractors have been slower than F12 though. Usually F/10 or faster.

For visual use I recommend either the Lumicon, Astronomik or Tele Vue Bandmate II O-III filters. They are expensive but I've tried a lot of filters over the years (including the Baader visual O-III) and the are simply the best performers with the most significant visual impact on the nebulae.

The earliest Synta / Skywatcher branded ED doublets had blue tubes. They switched to the champagne / cream colour scheme when the ED120 was launched sometime after the 80 and 100. The specs also claimed that the objectives were hand finished but that is a loose term that could mean a lot of things ! Back then the rivals didn't seem to specify glass types used unless it was fluorite so its not easy to tell what was used in the few non-fluorite ED doublets around back then. Back to today and the challenge that Skywatcher face is: - Forums extensively discuss the minute details of specification and rumours (correct or incorrect) travel fast. I believe this does influence customer demand. - There are many competing brands who do specify the glass types used. - We are used to increased levels of information regarding products and regard a lack of such detail as suspicious rather than meritorious.

I agree - Messier 31. I think you have also got the fainter Messier 33 as well - I've marked it in this copy of your image:

The Meade Polaris is basically the same scope as the Skywatcher 130p but with a single axis motor drive included. Made by the same manufacturer (Synta) I reckon. I agree with the wisdom of buying from a reputable astro dealer such as First Light Optics.

The AZ100 is a lot heavier and more solid than a Skytee II, is better engineered and has a higher capacity. It's a lot more expensive as well of course. @Stu knows the AZEQ6 well and can comment on how that compares with the AZ100 I'm sure. Personally I would want to hold onto a lighter AZ mount as well though so I would have held onto either the Skytee II or the Ercole. Not sure which would have got the vote but its academic because I'm not purchasing an AZ100 !.

Have you checked that your focuser optical axis is accurately aligned with the optical axis of the objects lens ? Thats the first check to make. I use an accurately collimated laser collimator to do this check. Put it in the focuser without a diagonal in place and see where the laser beam exits the objective lens. If its right in the centre, all is OK. If it is off to one side or other, the focuser alignment needs adjusting. When you are confident that the focuser and objective optical axis are aligned, then you can use the cheshire to check objective tilt.

Its funny how threads and posts get truncated by the "Recently Posted" preview pane. Peters last post comes over as this. Poor Helen ! Helen Sharman. By Peter Drew · Posted 8 minutes ago You can always smear some Marmite on them if they're too sweet for you Olly. 😃

Your additional tools suggestions are good ones

Hi Popeye, This is a good web article on star hopping which includes advice on method, tools and some targets including star maps: https://britastro.org/node/12846 My favourite star hopping tools are: - The Sky and Telescope Pocket Sky Atlas - A red torch to read the above - A zero magnification finder such as a Telrad or Rigel Quickfinder Here is a link to a more in depth and challenging set of hops to aid a messier marathon by Rob Hawley: https://www.robhawley.net/mm/SHG-MM-text-v6a.pdf

I don't know exactly what the figure is but the Baader Q-Turret 2.25x barlow increases the eye relief by around 30% I believe. All the 1.25 inch Hyperions except for the 24mm have optical elements within their 1.25 inch barrel sections as I recall. I'm not sure about the Explore Scientific 68 degree range. If you ask a specific question on this in the eyepiece forum I guess those who own them will give you the information you need.

I have read very mixed opinions on that since Skywatcher decided not to state what glass types they use. Personally I would like to know this information but I also understand that it is just one factor amongst many that determines how a scope might perform. It is interesting that Skywatcher heavily promoted that they used an FPL-53 element in the Evostar ED doublets from when they were first released over a decade ago. Not so shy about that back then ?

I think that ad might be referring to the highly praised original Evostar ED Pro, ie: this one: https://www.firstlightoptics.com/pro-series/skywatcher-evostar-80ed-ds-pro-outfit.html

Assuming that Betelgeuse does not go supernova before the 10th of course ! Even that would probably be clouded out with the weather that we have had lately

Crab nebula expansion has been captured:

Just a quick "bump" to this topic because Bristol Astronomical Society are running another Young Persons Astronomy Course starting on Friday the 28th February for 4 weeks. Here is a link to the Eventbrite booking page: https://www.eventbrite.co.uk/e/young-persons-astronomy-course-9-11-tickets-88371731227

The Aero ED eyepieces are pretty decent 2 inch eyepieces. They can be bought for around £50-£60 apiece on the used market. They are better corrected than the lower cost 2 inch eyepieces and also reasonably light for 2 inchers. They have a 70 degree apparent field of view and come in focal lengths of 30mm, 35mm and 40mm. The range of focal ratios of your scopes (F/4.7 to F/7) is reasonbly wide. The F/4.7 will pose the greatest challenge for an eyepiece in terms of remaining sharp across the field of view so you may need to accept some compromise there unless you are prepared to spend big bucks or stay with a smaller apparent field.

Thanks for the heads up about this event Simulating this in Stellarium makes it look rather unspectacular - penumbral eclipses cause more of a slight darkening of the surface than the "blood red" effect don't they ?

Here is a link to something similar to the process that Steve / Woodblock describes: http://www.stark-labs.com/craig/llcc/llcc.html