johnturley

I think there will be import duty (somewhere in the region of 10%), I had to pay this when I imported an Astro Physics Refractor in the 1980's, and the 20% VAT will be charged on top of everything including the carriage charges. The courier may also add on a customs clearance charge, although I avoided this by picking up the telescope from the bonded warehouse at Heathrow, and filling in the paperwork (I expect its all electronic these days) myself, so not very good news I'm afraid.

John 

3 hours ago, John said:

Has anyone used one of these 2 inch format long focal length eyepieces in a refractor with a focal ratio of F/7 ish ?

I'm wondering how they do, edge correction and other distortions at that focal ratio, actual AFoV delivered etc, etc.

Can anyone shed any light (so to speak 🙂) on these ?

StellaLyra 40mm 2" KITAKARU RPL Eyepiece | First Light Optics

StellaLyra 45mm 2" KITAKARU RPL Eyepiece | First Light Optics

Many thanks in advance 🙂

With these eyepieces only being 4 element, I can't see them being very sharp at the edge of the 65 degree field.

John 

32 minutes ago, John said:

Towards the end of August for a possible improvement ?:

UK weather: When will it stop raining and the summer improve? - BBC News

According to the latest online BBC forecast, there might be some improvement by 11 August, just in time for the Perseids. 

39 minutes ago, michael8554 said:

You'll have to explain what you're trying to do with 3 cameras, some mono.

The most common setup is a DSLR with a wide angle lens.

The ASI178MM/MC has a tiny sensor.

Michael

Some ZWO Cameras, including my ASI 462 MC, come with an all sky lens, don't know whether the OP was talking about using the lenses that come with the cameras.

John 

Have now booked the Mexico Tour 4 with Astro Trails, paying a 50% deposit, I have also booked return flights from London Heathrow to Mexico City with British Airways via their partner Star Travel. Booking the flights via Star Travel worked our slightly cheaper than booking direct with British Airways, the cost of which has gone up by around £500 pp since the beginning of June. I also thought that booking via Star Travel would work better if Astro Trails for any reason decided to amend dates, or even cancelled the entire trip.

I would be interested to hear from anybody who has also booked this trip, or any other trip to view the 2024 Mexico/USA Total Solar Eclipse.

John 

9 hours ago, Mark2022 said:

The thing is John, I would really like to have the ability to slip whichever eyepiece I wish to use into an adaptor. I have a Meade 9mm and 15mm plossl as well as 20, 25/6, 32 and 40 and even the 4mm, however only the 4, 9, 15 and 20 will fit the eyepiece adaptor I already have. I bought the Altair LER 5mm for the significantly increased eye relief at high power and I also thought this would provide a far brighter image on the camera.  I  have yet to  find out.

Mark

I think that you will find that the 5mm eyepiece will give too large and dim and image with a digital SLR having an APS-C sized sensor, making it difficult to achieve correct focus, and tracking will also be more difficult. I think that your 9 or 15mm Plossls will yield better results.

John 

4 hours ago, Mark2022 said:

Well that's odd because when I type the same in, nothing comes up except garbage totally unrelated.  Anyhow, I've found what I'm looking for BUT at a cost. It is a Bresser and accommodates up to 55mm body diameters. £55 though. So for anyone looking for similar,  here it is... https://www.bristolcameras.co.uk/product/bresser-variable-camera-adapter-1-25-inch-4940130/

Maybe cheaper overall to buy a cheapish 10-15 mm Plossl, such as from the Astro Essentials range available from FLO, that should fit in a more traditional sized (and cheaper) eyepiece projection tube such as the one listed below.

Astro Essentials Super Plossl Eyepiece | First Light Optics

Tele-Camera Adaptor for Eyepiece Projection Astrophotography | First Light Optics

John 

I suspect the problem is due to lack of travel on the focusing mounts, at one time most refractors had focusing mounts with around 5in (125 mm) of travel, some now however have only around 40 - 50mm (which I consider totally inadequate), and require the use of extension tubes with some eyepieces. As a bare minimum I consider that there should be at least 80mm of travel on the focuser.

John 

42 minutes ago, AstroKeith said:

The idea is that your finger tips are very sensitive and will tell you if you are dragging dirt/grit across the surface, whereas cottonwool etc will just go ahead and do the damage.

For eyepieces I use a reverse rolling technique with cottonwool, which lifts dirt away from the 'wipe' but means you need a new swab every 50mm or so of sweep. This isn't practical for a mirror, so fingertips for me.

The coating is actually quite hard, but cannot resist scratching from grit. Wet finger tips won't harm it.

I actually prefer to immerse my mirror in a bowl of lukewarm soapy water first, and leave it to soak for about 30 minutes to loosen any grit, and then rinse before swabbing.

John 

7 minutes ago, Louis D said:

From this telescopeoptics.net eyepiece spot diagram collection, it's pretty clear that Abbe Orthos fail to keep the image rays within the airy disk at f/5 (first spot diagram column) off axis, and do much better at f/10 or especially f/15:

 

Thus, it makes sense to slow down the incoming light cone from f/5 to f/12.5 with a 2.5x Powermate.

Or use a Nagler or other design of eyepiece with an in-built Barlow.

John  

27 minutes ago, AstralFields said:

There are some studies out there which show that reflectivity drops every month of continued use. By how much it depends on the amount of use/environment etc.

1997PASP..109..303M Page 304 (harvard.edu)

I cleaned mine after about 20-30 nights of going out during a one year period (it was a busy year). Did it for the first time and made a video about it to show how easy it is, so people are not afraid to do it.

I am not so concerned about reflectiveness as such but a fine layer of dust causes also light scatter. Not to mention insect c*** can react with dew and damage the coatings. Especially if the scope is brought indoors where condensation may form on the mirror. That is bad enough already but add a lot of dust mixing with it and that can't be any better than washing the mirror twice per year.

Just make sure to do it right! Lots of bad advice (cotton swabs) out there on YouTube. That can end in a disaster real easy. Another reason I made my video.

 

 

Not so sure about using fingers rather than cotton wool swabs.

John 

4 minutes ago, Astrobug said:

The plan is to use it with the zwo 2600mm , 33mm will do the job but no pictures to find with these small pixels. You use it with your 6D?

Yes I use my 6D with the Esprit, it fully illuminates the 36 x 24 mm full frame format, but would apparently not do so with the reducer, but you should be fine with the ZWO 2600, which I understand has an APS-C (24 x 18mm) sized sensor.  However with the 6D, I do need to use a 48mm to Canon adaptor, as I found that there was some vignetting with a 42 mm T thread adaptor. 

I thought of getting one for my Esprit, but was put off because apparently when using one, it won't fully illuminate the field of a full frame sensor, the 44mm imaging circle being reduced by  0.77x to 34mm. 

John 

6 minutes ago, Nicola Fletcher said:

My new FC100DZ, set up but no stars to be seen yet. I can’t wait to get it out for first light. I was so tempted to get the TSA120 instead but went with the DZ to get a bit of extra aperture but keep the portability that I like from the FC76. 
 

In a fit of frustration at the clouds, last night I ordered the Baader 2” BBHS mirror diagonal and the 41mm Panoptic for some widefield views if the weather ever improves. I’m a bit apprehensive about the size of the gigantic Panoptic but the 24mm is so much fun in the FC76, I thought the big brother in the DZ could be great. Let’s see if my mad plan works out!

Looks like you've got it mounted on a Skywatcher AZ-EQ5, which should be more than adequate.

John 

37 minutes ago, GMFoods said:

Thanks, wasn't aware of the 50° limitation at 32mm.

I'll definitely get the ES 24mm eyepiece, is there any point in getting a televue plossl 32mm as well, or will they just give similar performance?

For planetary I think I'll stick to the zoom for the time being and try to do more research.

There would be no point in getting a 32mm plossl as well, as they both have around the same actual field of view despite the lower magnification of the 30mm plossl.

John 

On 14/07/2023 at 17:47, Louis D said:

Thos eyepiece projection adapters haven't changed in 40 years.  They were intended to be used with the Kellners and Orthos of the day.

That being said, why would you want to push your SCT with the equivalent of using a 2.5mm eyepiece?  It already has a ~2000mm focal length natively.  Going to projection with a 2.5mm eyepiece is going to massively increase the image scale.  The f-ratio is going to drop from f/10 to f/400.  That's insanely slow with a 0.25mm exit pupil.

Why not just try using the DSLR natively on the scope with a 1.25" or 2" (depending on your visual back size) to T-thread adapter?  Guiding a 2000mm focal length scope is difficult enough.  From there, you could progress to high powers with the Barlow alone if you think you still need more magnification.

Maybe I'm misunderstanding your use case.  What do you plan to image/photograph?

As Mark has stated, using the DSLR natively will result in an image scale far too small on planets, and a 2x Barlow alone won't give sufficient amplification. Having said that a 2.5 mm eyepiece with ~2000mm focal length almost certainly gives too much amplification, and make it difficult to focus.   I found that with my 14in Newtonian (~1800mm focal length), and Canon 6D full frame digital SLR, I got a reasonable image size on Jupiter with a 9.7mm plossl. With a cropped APS-C sized senor sensor, a 12-15mm eyepiece will probably be about right. I kept the 15, 12.5, and 9.7 mm eyepieces from my original set of smoothside Meade Series 4000 plossls specifically for eyepiece projection, a lot of modern eyepieces will be too fat to fit in most eyepiece projection tubes.

Having said all that, you will get much better results with a dedicated planetary camera such as the ZWO 224MC which is not too expensive at around £200, as these have a much faster frame rate, allow more cropping than most digital SLR's, and the associated software (I use Sharpcap, followed by AutoStakkert and Registax) makes processing easier.

For comparison I attach 2 images of Mars taken through my 14in Newtonian showing roughly the same surface features, the first was taken October 2020 using eyepiece projection with a 9.7mm plossl with my Canon 6D, the second using a ZWO ASI 462 Planetary Camera with a 2.5x Powermate taken in December 2022 clearly shows much more detail, despite if I recall correctly, more detail was visible visually in October 2020 when Mars was much closer.   

16 minutes ago, Louis D said:

It's your focuser that is the problem for having a compression ring to snag in an undercut according to him.

I don't find undercuts a problem with the Baader Clicklock system.

John

1 hour ago, gorann said:

Out of curiosity: what company made the "Andromeda" telescope. It is impossible to google "Andromeda telescope" and getting anything but M31 images.....

Looks a bit like one of the 4 .5 in Refractors that  Astronomical Equipment (Luton) used to manufacture in the 1970's and 80's.

John 

Will look out for it when we see the total eclipse from Mexico next April, although I gather that its only likely to be a binocular object.

John 

6 minutes ago, Louis D said:

BTW, does anyone know why the current popularity of unboxing videos exists?  I find them completely uninteresting.  At the end of the video, I still have no idea if the item is any good for its intended use.  I only include images of the packaging in my reviews to satisfy those who find that sort of thing essential to a review.

I assume that some people do it to prove that the item was in condition it was at the time of opening, useful perhaps if the item has sustained some damage in transit.

john 

4 minutes ago, yuklop said:

Hi All,

I have a fantastic old telescope shown in the picture below. Its does a great job, but it is 31kg, and as such one can't just whip it off the mount and use shorter focal length OTA's on a whim. I used to really enjoy experimenting with different OTA's. So I really want to mount a second OTA, e.g. a 4'' refractor for wide(r) field views and the odd photo.

I could try and piggyback it on the Cass, but that adds even more weight, and even more counterweight. What's your thoughts about mounting a second scope on the counterweight side of the mount, so it effectively acts as a counterweight itself. Or does that result in balance hell? Anyone done something like this before?

Thank you.

Dan

Interesting looking mount, it looks like an Astro Systems (Luton) or a Bedford Astronomical Supplies (Peter Drew) one. 

John 

19 minutes ago, Zermelo said:

Have you seen this thread?

 

When you get to my age, its easy to forget what you posted 3 years ago.

John 

2 minutes ago, bosun21 said:

Thanks. I was thinking about using it on my 12” dobsonian on an EQ platform. Thoughts?

It was quite effective on Jupiter and Saturn through my 14 in Newtonian when they were quite low down, but did not make so much difference through my Esprit 150.

Now Jupiter and Saturn are moving higher up it will make less of a difference, I don't think many people bother using them for AP as you can correct any false colour due to atmospheric dispersion in the processing software.

John 

25 minutes ago, NGC 1502 said:

Indeed, with most reflectors that’s true.  Not so however with AstroSystems Newtonians.  The whole primary cell with mirror attached to the tube with tiny precision screws.  It was a simple job to remove, clean the mirror and reattach with collimation unaffected.  Tape could be applied around the edge of the mirror and cell so the felt between mirror and cell did not get wet.

Simple, effective, brilliant 👍 ……..sadly they don’t make them like that now!

Ed.

That's similar to my 14 in Newtonian, I've never had to re-collimate the primary, just the secondary.

John 

Has anybody booked, or thinking of booking, one of these trips with Astro Trails? We (my wife and I) are currently looking into booking with them to see the April 2024 Total Solar Eclipse from Mexico. Originally we thought of doing the trip they were advertising to view the eclipse from near the Niagara Falls, followed by a trans USA Amtrak Rail Trip across the USA visiting New York, Washington, Chicago, Denver, and ending up in and flying back from San Francisco. However Astro Trails informed us that they are no longer offering this trip due to lack of interest, so looking at the Mexico trip instead. 

We had a very successful trip to see the 2019 Argentina Total Eclipse with another company Astro Eclipse, which was well organised, however as far as we can see this company no longer appears to be operating. Although their website is still live, it is out of date, and there is nothing available to book at present, hence looking at Astro Trails.

Astro Trails currently require a 50% deposit to book, with the balance to be paid by December, which is similar to what Astro Eclipse required, we appreciate that its not like booking a holiday with JET2 or TUI, where you just need to pay a £60 pp deposit, with the balance not due until about 10 weeks before the departure date.

Unlike Astro Eclipse however, Astro Trails do not include International Flights in their price, or even transfers from and to the International airport, you can either book these yourselves, or via their partner Star Travel. Either way the full cost of the flights is due at the time of booking, which means that I would have to pay out about 2/3rds of the total cost now. I am therefore a little  wary about having to pay out so much, especially for the flights, 10 months before the departure date.

John