Merlin66

The serial number is just a guide.

A better question to ask would be - does the front objective look "blue" or "brown/ gold"

Don,

I have a late five element 4000 no eyecap made in Japan, recessed barrel circa 1990.

Let me see if I can help....

The Series 40000 super plossls are "Ok" eyepieces BUT they come in two flavours.

The original design was a five element design said to be based on the mythical Masuyama five element design. These are collectables.

They are marked JAPAN on the barrel, and do NOT have rubber eye caps and were manufactured prior to about 1996 by KOWA.

The early Kowa versions were smooth barrels but the later versions circa 1994? were undercut.

The rest were made in China and changed back to four element design to save $$$$$ ???? which was pretty "basic"

Hope that helps.

Ken

(I have a remaining sample of the five element design from1995. I did have a full set of Masuyama eyepieces (!!!!) which I sold to buy Ha solar filters.)

With the TSO my C11/NEQ6 was covered by a dust sheet and in winter after an observing session I draped a 12v heated doggie blanket over to reduce dewing.

It’s done well for almost ten years.

The objective lens was a 2” spectacle lens blank, 1 diopter ( 1 metre focal length).

A photo of the set up would help.

usually it’s possible to slide the OTA in the rings to allow the focuser to clear the rail.

Nicolas,

I thought the HD version had the mirror lock screws to prevent movement?

The slop can be reduced by running the mirror up and down the baffle - about thirty turns of the focus knob.

This redistributes the grease and reduces the gap between the mirror sled and the baffle.

Doing this every month or so definitely improves the situation.

works for both Celestron and Meade SCTs.

+1 for Astroart - it punches well above its weight!!!

Even with a rear crayford etc, the mirror is not fully restrained and can still flop.

You can use the Auxiliary mount option to allow RA/Dec feedback from the mount.

The filter can fail within months, or years.........

No guarantees.

It's associated with the construction of the filter, the glass is hygroscopic, similar to the older photometric green V filters.

https://glassfab.com/wp-content/uploads/2015/08/schott_filter_catalog.pdf

(see sect 5.5)

I’ve been using PHD2 with ST4 connections with my NEQ6/ C11 combo for many years.

It’s not necessary to recalibrate between targets if it’s set up correctly.

Pretty good, mate!

Looks like dust bunnies on the RHS - probably on the camera cover plate?

Barry,

Pity about the spelling error on the hand control box - not a good look….

Nice collection!

which target wavelengths were you using?

Adam, et al,

Baader solar film is 100% safe to use if it is properly looked after and secured to the telescope.

My Baader film is over 15 years old and still as good as the day I bought it.

They say the replica is a Mk9, but the canon layout is that of the Packard Mk16.

https://www.rafmuseum.org.uk/research/collections/supermarine-spitfire-mk-xvi/

Thanks Pete.

Pete,

Thenks mate, appreciated!

I agree with Geoff.

make a couple of masks/ holders for the D-ERF one for each scope.

unless you have phenomenal seeing conditions a 135mm aperture for solar is pretty good.

There's a tremendous resource at :

https://www.blocklayer.com/timing-tape.aspx

all sorts of tapes and disks, very handy for the amateur.

NiCo10,

The Lunt CaK module is still available. https://luntsolarsystems.com/product/lunt-calcium-k-modules/

Note, the Lunt is quoted as 2.4A bandwidth. My DIY version is a 25mm double stacked assembly and gives 1A bandwidth.

Thanks for the feedback, appreciated.

I'm quite pleased with the performance of the Vixen Custom90 at the CaK wavelength.