johnturley

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 Although their website is still live, it is out of date, and there is nothing available to book at present, hence looking at Astro Trails.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  

6 minutes ago, Marvin Jenkins said:

I didn’t add my name as my domicile is France. Furthermore I am not allowed a vote in the UK or here. 
In fact I am not allowed to vote in any election vote or referendum at all.

No taxation without representation 🤣 oh no! Have I broken the no politics rule? 
Marvin

It's the same as in the UK, my wife has lived in the in the UK for nearly 25 years, however she isn't allowed to vote in General Elections (only Local Elections) and wasn't in the EU Referendum.

John 

If you replace the 1.25 in nosepiece on the filter wheel with a 2 in nosepiece, you might find that you have just sufficient 'In Travel'

I fitted a 2 in nosepiece to my ZWO filter wheels, which gave my about an extra 10 mm of in travel, which was sufficient in my case, it all depends on the scope.

In addition it is possible to move the focusing mount slightly towards the main mirror which will give you extra effective in travel, but this will involve drilling new holes in the telescope tube, which I understand not everyone would want to do.

John 

16 hours ago, Nakedgun said:

~

Very recently, Explore Scientific had an eyepiece sale on several of their lines. Of particular interest to me was the pricing on some of their 82° series.

Having already acquired all the 5/4" models in this line, the pricing on the 2" units pushed me to finish the set, otherwise I would not have.

 

 

 

 

Now, they're all collected in one place, but, I have a problem, as you can plainly see - an empty gap in the case. 

What to do?

 

 

 

 

.

Maybe an ES 2in 2x Barlow would fit in nicely

John

3 hours ago, tomato said:

Anybody else having problems accessing this site? I have been getting ‘technical problems with the site’ for some time now.

I've just accessed the site, and it seems to be working fine.

John 

On 13/05/2023 at 10:03, 900SL said:

Hi

I am setting up a manual rig for the holidays. I have 360 degree panoramic rotators on the RA and Dec axes as below

 

If I want to use these to 'star hop' to a DSO target, is the following procedure correct?

Align lens with a bright star, example say Vega,  same side of meridian as target, note the degree readings on RA and DEC angular scales

Work out difference between target RA and DEC and Vega RA and DEC (and convert RA hrs mins sec to degrees). I'd probably do this in advance on a spreadsheet on my tablet and using stellarium web)

Adjust the RA and DEC axes accordingly

I'll be widefield with a 135mm so getting it dead center isn't critical, I'll plate solve as long as I am approximately on target

 

An easier method if your mount has setting circles and a meridian pointer (which I use with my 14 in fork mounted Newtonian) is via a sidereal clock, although you don't need an actual clock these days as sidereal time for your longitude is available as an app on iPhones. You simply set the meridian pointer to local sidereal time on the RA Circle, and then move the scope to the RA and Dec of the desired object, assuming of course your mount is reasonably well polar aligned.

I find this particularly useful for locating Mercury and Venus in daylight, when you can't star hop. The problem is that most scopes that actually have setting circles these days, is that the circles tend to be too small, ideally you need an RA circle at least 12in in diameter, my fork mount has a 12in RA circle with each hour subdivided into 20 minute and 4 minute segments. 

John  

Ed said that he liked eyepieces with a dual 2in/1.25in barrel which used to be quite common.

Personally I disliked them as it made the eyepieces more bulky and heavier than they otherwise needed to be, and I was always dropping the removable screw and then having to search for it in the dark.

I agree with him however that it was a shame that Tele Vue discontinued their 26 mm Nagler eyepiece, I was until recently on the look out for a good secondhand one, but opted instead for a Stella Lyra 30 mm UFF, which cost new less than half of what I would probably have to have paid for a secondhand 26 mm Nagler. 

John 

I always say that the ideal punishment for those opposed to adopting the Metric system, would be to lock them in a room, and then make then do Physics and Engineering calculations using old Imperial units.

I still however remember the diameters of the planets, and their distances from the sun in miles. 

John

Amazing that you could make out the North Polar Cap on Mars with the tiny disc now less than 6 arc seconds.

John 

10 hours ago, Oxize said:

Is this to much shift? Or is it normal (5x digital zoom on DSLR).

 

Unfortunately I do not think that the stock focusers on the Esprits are up to coping with heavy accessories such as a digital SLR, on the other hand I do not find much of a problem with my ZWO ASI 462 camera mounted on my Esprit 150 with the stock focuser.

John 

Observed Venus while it was still quite high up in the early evening yesterday, and which was displaying a nice gibbous disc.

Whereas Venus at magnitude -4 was quite easy to find in daylight with my old fashioned setting circles and sidereal clock, I was unsuccessful in trying to spot Mercury at magnitude +1.4. I put the failure down to insufficient contrast with the bright early evening sky before Mercury went down behind a neighbouring house. I find Mercury fairly easy to pick up in daylight when it is brighter than zero magnitude, it becomes progressively more difficult between zero and +1, and very difficult to find when fainter than +1, although I have managed it on previous occasions depending on sky transparency.

John  

52 minutes ago, Louis D said:

The original Vixen LVs from 7mm on down were all 45 degrees.  I can't remember if they changed the claim to 50 degrees with the NLV or SLV line, but the actual optical design didn't seem to actually change, just the claims.

It actually states 50 degrees on the barrel.

3 hours ago, John said:

This review by the late Tom Trusock dates back to 2004 but I feel it still has some validity today. The comparison here is with the TMB Supermonocentric eyepieces which are regarded by many as some of the very best of the specialized high power eyepieces:

Cloudy Nights Orion TMB VS Nagler

I've owned a few of the shorter length Vixen LV's over the years and they are very comfortable and sharp eyepieces. I felt that the ones that I used put up a slightly dimmer view sometimes than, say, a conventional ortho of the same focal length. I have seen throughput data for some eyepiece ranges that seems to confirm that the LV's are on the lower side. Still very useable though. I did feel that the Vixen SLV's took the LV concept and improved on it. The 6mm SLV was particularly nice I seem to recall 🙂

I have both the 3-6 mm Nagler Zoom, and a 4mm Vixen SLV, I find the results with the Nagler Zoom on the moon and planets to be at least as good as the 4 mm SLV, and has a significantly wider field of view. Although it states 50 degree APFOV on the Vixen SLV, I find it to be nearer to 45 degrees.

John 

11 hours ago, Ratlet said:

 

I'm currently just playing with eyepieces mostly to figure out what works for me and I was thinking the next would be an ultra flat, initially looking at the 30mm Stellalyra UFF to replace the 30mm superview.  I'm now thinking it might be an idea to try a 15 or 18mm ultraflat instead if anyone has experience of them.  I tend to mostly observe with the 16mm so it does kind of make more sense for comparative purposes.

Feedback greatly appreciated.

I can recommend the Stellalyra 30mm UFF, it works quite well in my f5 Newtonian, although the edge is not perfect, it is vastly superior to my 36mm Baader Hyperion Aspheric. 

John 

I tried silvering a mirror (Brashear's process I think) while I was at school in the late 1960's, it wasn't very successful, the coating was very thin, and rubbed off when I tried to clean it. 

Even if successful silver coatings used to tarnish quite badly after only 6 months, at that time aluminium coatings used to last about 3-5 years. Nowadays modern enhanced aluminium coatings, such as Hilux offered by Orion Optics UK if looked after, last at least 10 years.

John 

I don't usually use GOTO for the simple reason that my main scopes (14in Newtonian with Esprit150 piggybacked) are mounted on fork equatorial mount made by Astro Systems (Luton) in the 1980's, which doesn't have GOTO, and it would either not be possible, or prohibitively expensive to install it. 

It does however have a meridian pointer and large setting circles, which in conjunction with a sidereal clock (actually use an app on my phone now), I use to locate objects not visible to the naked eye, or Mercury and Venus in daylight. 

John 

On 04/02/2023 at 17:13, iantaylor2uk said:

I'm surprised you can't buy a "modular" mount, in which the mechanics and the electronics are completely separate, so that the user could choose what motors and control systems to use on the mount.

I guess the closest company that comes to this is Losmandy - all that sticks out from the mount are the ends of the worms, and you can attach different motors onto this (for example, I first bought a G11 with a 492 push-to system, back in 2009, but recently upgraded to the Gemini-2 system in 2020, which meant changing the motors and gearboxes and changing the controller box). However, some others use their Losmandy mounts with OnStep or EQStarPro systems (because they didn't want to go to the expense of the Gemini system).  

The problem as I see it is that you have either (1) good engineering companies that then put cheap (or very expensive) electronics on their mounts, or (2) companies that are good at the electronics side but may be poor on the mechanics side.

I've seen lots of posts on forums where people have old mounts and have had endless problems when the electronics on those mounts have died. 

If there were people that made such mounts it may also stimulate innovations in the control and electronics side so we see more than just OnStep and EQStarPro, and this could lead to lower prices in the longer term.

Not sure what people's thoughts are on this, but to me it seems to me some people would be interested in such mounts. 

 

That's pretty much how things were 50 years ago in the 1970's, Fullerscopes and Astronomical Equipment (Luton) were prime examples, in fact they were just about the only producers of mounts in the UK, later joined by Astro Systems and Bedford Astronomical supplies. 

You could purchase the mounts with or without slow motions, synchronous motor drives or Variable Frequency Oscillators, or add them on a later date. Limited technology maybe, but no complicated motherboards to burn out. I have a 40 year old mount from Astro  Systems, the original RA and Dec motors are still in working order, and touchwood will remain so the the rest of my observing days (I'm currently 73 years old !)

19 hours ago, Moonshed said:

I purchased the above a couple of years ago to plug into my flip mirror box. It has been such a great aid so now it’s stopped working I need to replace it. I thought I could just buy the illuminate part that screws into the eyepiece but it appears that I need to purchase the whole thing again, which seems to me to be a bit of a waste.

Am I right in thinking the two parts are not sold separately? I have looked in so many places but have made no progress, it appears I have to buy the eyepiece as well.

The Widescreen Centre , which I think is not too far from you, sell this eyepiece and illuminated reticle, both of which can be purchased separately.

I have one of these, and touchwood not experienced any problems, changed batteries (LR44 I think) a few times

TS-Optics 23mm 1.25" Illuminated Crosshair Eyepiece - Widescreen Centre (widescreen-centre.co.uk)

John 

30 minutes ago, Jim L said:

I purchased this rechargeable air dusted a few days ago:

https://www.amazon.co.uk/Reesibi-Strongest-50000-90000-Compressed-Rechargeable/dp/B09QX59BNK?ref_=ast_sto_dp&th=1

I chose this particular model over it’s competitors because it has a brushless motor.  Will the brushless motor make a difference in performance or durability?  I’ve no idea but I figure it can’t hurt and here in the States it’s the same price as the bushed motor models.

My region of California is semi-arid and that means lots of dust.  The rechargeable duster works brilliantly for removing that dust and is far superior to both the squeeze bulb dusters and the canned air.  It moves a lot of high velocity air without the potential danger of blasting your optics with propellant or other undesirable compounds, and it’s far more powerful than any bulb duster.  My only regret is not having got one earlier.

 

Do you think that the rechargeable duster will provide a jet of air as powerful as the Kenair Air Duster, I usually get through one refill per year, and I notice that the cost of these on Amazon has now gone up to £20, and as you say the problem with these is that you have to be careful not to tilt them in use, otherwise propellant can get on your optics.

I've just looked on Amazon now, and found a cheaper model at £39.99, don't know whether it would be as good as the Reesbi one, it says up tp 90000 rpm though.

https://www.amazon.co.uk/Electric-Compressed-51000-90000-Rechargeable-Electronics/dp/B0BR9C7X6S/ref

John

3 minutes ago, matija said:

@ONIKKINEN I am using a cmos camera and as such it doesn't have hardware bin so binning wouldn't help at all. Here is an image.

Looking at the above image, it appears to be out of focus, but at least the star images seem to be quite symmetrical discs indicating not a collimation problem

John 

I think that the William Optics scopes are generally regarded as being of better optical quality, and better engineered.

John 

2 hours ago, Mr Spock said:

I've recently been using the SL 30mm UF in my 12" f5 Dob. I can report that the last 2-3° needs refocusing to get it sharp, but, once focused there's no trace of coma. 

I was testing it last night on a few wide doubles and when refocused the stars were perfectly formed and very sharp.

Agree, I find that with the StellaLyra 30mm UFF in my f5 Newtonian, stars at the edge of the field are not in as sharp focus as those in the centre, not that they suffer from coma, but can be re-focused.  With my Baader 36mm Hyperion Aspheric on the other hand, I get seagull shaped images at the edge, which cannot be brought into sharp focus, and which benefit from the coma corrector. 

John