wxsatuser

2 hours ago, Nakedgun said:

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Is there no Nikon/Canon adapter available?

 

 

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There is

Astromechanics Ascom Canon lens controller.

May be hard to get one as they are Russian and importing might be hard.

Plus not cheap.

Be aware although a very nice lens old versions may have issues with CA etc.
You may get a good one or not.

Looks like the underneath of a Boeing 737, when retracted the main gear still shows.

Nice one.

One taken by my sister on an iphone

On 15/10/2023 at 15:02, Macavity said:

Further aside: I don't think I have ever heard quite so much activity
on the HF amateur bands (20m (17m) 15m (12m) 10m) as now. 
Just put up a new (rather short) "long wire" antenna too. But,
whatever the "Solar Activity", something is working! 😉

https://www.qsl.net/4x4xm/HF-Propagation.htm#Reg2
 

Last weekend was pretty good on ten metres, got into the Maldives and South Korea.
Twelve metres was roaring as well, got into Botswana for a new country
Twenty metres was excellent to, got into Australia, New Zealand, USA and Japan.

Conditions do vary quite a bit as the Sun gets it act together.

BTW I run a maximum of 100watts of FT8/FT4 to a cobweb 5band antenna about 24feet agl.

You will most likely not find to much activity on 23cms, really depends on conditions and if your near any centres of activity.

Some of the best ham frequencies to check will be the FT8 ones, if there is any activity it will be on these frequencies.
144MHz......144.174MHz
432MHz......432.174MHz
1296MHz....1296.174Mhz

Best to watch for good tropo conditions and keep an eye on DX clusters.

For tropo conditions try Hepburn
For DX Cluster and pick a band to see what is being heard and where.

You could try beacons a list here

I knew I had one some where.
It's quite big, just about fits in my hand.

This is pyrite found on the local Downs.

We used to collect these on the local Downs just after the plowing, they were easy to spot amongst the flints.

All us kids called them meteorites but we knew they were not.

Sad to hear it.....RIP John.

Zilch is a good word for it.

14 hours ago, geeklee said:

I think you're making life unnecessarily complex for yourself doing this.  Not sure about the 1/3rd distance from the left - that might be a DSLR thing? 

You are correct as the 20>30% histogram thing is to gauge where the RAW histogram is just detached from the lefthand side with a dslr.

It is this value because one would normally view the histogram on the back of the camera where the image is a processed jpeg.

I got one last year, seems a nice bit of kit.

Yet to use it in anger. 😀

Just one other little tip.

If the supply side neutral breaks on a TN-C-S  supply the RCD will not trip as it will still carry equal current in each leg.
Current flows through live round the appliance via it's neutral and back to the appliance earth terminal making the metal appliance
live, if you touch it you complete the circuit to earth.
This is why powers that be don't recommend any metal appliances outside on a TN-C-S supply.

If the power goes off do not touch anything metal and check to see if the supply side neutral is still there.

On 27/11/2021 at 12:56, M40 said:

As others have said, it's volt drop over distance that is your concern. 2.5mm for extra low volt IMO is not a starter. Put the power supply in a box and look to it being local to your stuff. I mounted the same supply in a box powered by a long mains lead, installed a set of connectors in the box, got rid of the cigarette lighter and ring lugs off the supplied cables and then just connected the supplied cables to the connectors. Job done.

I would be more concerned if that's a metal box and you have a TN-C-S supply.
A broken neutral will would make that box live and more than likely give a fatal shock outside.
There doesn't even need to be a fault in the box to make that box live if the neutral on the supply side breaks.

29 minutes ago, ollypenrice said:

 

Very few telescopes can cover a full frame (35mm) camera and the few that can are easily recognized by their price!

Olly

There are a very few camera lenses that can do it as well and they are also noticeable by their price.

19 hours ago, rnobleeddy said:

Having played with a few random old and new lenses, definitely do some research before buying. All lenses are not equal, and the cheaper zoom lenses that come with DSLRs have been pretty awful in my experience. On the flip side, some older prime lenses have performed well. If buying new, there are some threads here that cover some common good choices, like some of the Samyang prime lenses.

I would agree, very few lenses fit the bill for the best images and most are expensive.

I cannot comment on other makes but the ones I have tried and bought.

Canon 200mm f2.8 prime
Canon 70-200mm f2.8, the expensive ones.
Samyang 135mm f2

I have tried various Sigmas, 105mm macro is reasonable if you like widefield.

I have the version 2 that goes to 3ghz they say.

Going to actually use for the first time as I took down my cobweb antenna to put new
coax on it yesterday and two bands are a bit high swr wise, after putting it back up higher.

Some reason my Icom 7300 is struggling to match 15 and 10metres but the swr is not that bad really, about 2.5-1
The other three bands are nye perfect no matching needed.

Had to get the cobweb up higher to make sure I'm within the new EMF regs, mine is very close to our boundry
with three neighbours. Putting it up to about 8metres should let me run my full 100watts no problem.

23cms is very quiet here in  south central Sussex, takes some tropo or a contest to get stations out.

I can just hear the Martlesham beacon near Ipswhich using a Create 21element logperiodic attached to my
ICOM 9700. It doesn't beam my way, it beams east and west, you may be able to hear it.
When I beam towards it I get the Gatwick radar over loading my receiver.

That is better.

The worst area is bottom left, as above crop it out.

Unfortunately all Samyangs are not equal, some are better than others.

Some star trailing, focus seems good but in that test I would go with the kit lens at those settings.
Not what you want to hear no doubt but the Samyang has the obvious coma.
You should be able to shift the chromatic aberration with software and a lens profile.
Do this on the RAW file.

BTW the filter will shift the focus point as it's another piece of glass in the way.
I wouldn't worry about it as long as you get good focus.

The coma is not good if that is f/4.

Try the focus without the clip filter and see if it comes to infinity.

It has sagittal astigmatism/coma in the corners, the flying birds, with some chromatic aberration and vignetting.

Not unusual for a lens of this type, not massively obvious unless we pixel peep, about as good as it gets at f/2 imo.

For star clusters an unmodded camera is perfectly ok.

If you have a real dark sky there a 600D should pick up some nebs on long exposures as well.

My 6Dmk2 does release the shutter with out a lens, all my Canons do.

I would have thought that diagonal pattern is not right.

The column not a problem as such.

Going back a bit I had two stacked 55elements on 23cms, very sharp.

I hear there are fake Diamonds out there, buy from a reputable dealer to avoid disappointment.