Jm1973

What sort of mount is it? Goto or manual? Equatorial or Alt-Az?

Once you take the DSLR out and put a barlow on, you could easily have knocked the telescope off target.

You will also be zooming in further so you will be looking at a smaller FOV.

Plus the planets are moving too.

It can be tricky to find them, they are small and you are probably looking through a small live view screen.

I followed this guide

https://www.lightvortexastronomy.com/tutorial-setting-up-an-equatorial-mount-on-ascom-with-eqmod-stellarium-and-cartes-du-ciel.html

46 minutes ago, Snooze said:

I'm in a similar situation as OP and very interested in this thread. 

Correct me if I'm wrong but a 1min exposure without an Ha filter should contain the same Ha signal as a 1min exposure with a filter right? As far as I understand it, the point of narrowband filters is to let you expose for longer thereby increasing the useful signal(the DSO) compared to unwanted signal such as light pollution or sky glow. Is that correct?

A one minute exposure with an ha filter will actually have less signal, than a 1 minute exposure without one.

But for me,  even a two minute exposure, without a filter, is ruined by skyglow and LP.

On 01/12/2020 at 09:19, rnobleeddy said:

I'ma big fan of the dual band filters for a DSLR. They effectively split the Ha signal to the red pixels and the O-III to the G/B pixels. The width of the Ha  pass band aside, as far as I can tell, the concept is strictly better than Ha for DSLR's because you don't lose any Ha, and gain O-III for free. Practically, I imagine the Ha band is a lot wider in the dual band filters than a quality Ha filter though.

I'm always wary of posting images as I have a lot to learn - but this was less than hour of dual band data with a 450D on a night with 90% moon.

 

 

 

That's a nice East Veil pic. Which filter did you use?

There are quite a few dual-bandpass type filters now, often confusingly marketed as tri-band or even quad-band, but apart from the OPT Triad Ultra Quad-band, they are all just dual bandpass.

Sometimes the oiii band is wide enough to allow hb to pass as well, and a bit of clever marketing is to call these tri-band filters, rather than dual band filters with a less restrictive band-pass. 

If the Ha band is also a bit wide, enough to include sii then they call it a quad band filter.

In reality though, these tri and quad band filters are just less restrictive dual band filters - althought they may confer other qualities such as more natural star colour.

The l-extreme as it has two 7nm bandpasses, is good enough to filter out most light pollution, even moonlight, which most of the others won't block. The STC duo-narrowband is similar but more expensive.

The OPT Triad Ultra Quad-band actually has 4 separate bandpasses, one for each of the emission lines, but that is massively more expensive.

If you just want to dip your toe in the water, so to speak, the Altair Astro tri-band and the ZWO duo-band filters are the cheapest, at around £80 for the 1.25" version. They have, I think, 15nm ha and 35nm oiii/hb bandpasses.

The good thing about these filters is you can split out the oiii and ha into two channels and do dual-narrowband imaging in APP or PI.

Check the date format. 

I had issues where slewing was completely wrong, and it was because the date format was wrong. It should be entered in American format: ie. mm/dd/yy.

M42 is easy.

12 minutes ago, globular said:

I'd be interested in this too.

I have seen a fairly comprehensive impact assessment of different filters on different nebulae by Dave Knisely.....

https://www.prairieastronomyclub.org/filter-performance-comparisons-for-some-common-nebulae/

Should still be applicable I guess. Thanks.

Hi. Is there a website showing which emission lines are visible from which nebula?

I'm trying to work out which filters are suitable for which DSOs.

Thanks.

A lot of food for thought. I guess if I was going to go for the easy option I would get a jump-starter, as they seem to be basically the same thing as the SKywatcher powerbanks but cheaper.

My other option is to build something bespoke. I have basic soldering skills. I used to build drones and that involved soldering circuit boards, so something like this should be a doddle. I can certainly follow a circuit diagram. 

I suppose the other option is something more modern like LiPo or LiFePo. Am I right in thinking the main advantage with LiFePo over Lipo is safety? 

17 minutes ago, teoria_del_big_bang said:

Very much like myself then.

If you fly and maintain drones I suspect you would have little issues with buying a 17A/H  battery  and making a nice box with all the required connectors.

Personally, I think it would work fine for the small current you are drawing (probably no more than 1a most of time). If you are using Dew bands though this may add around another 1a to the draw.

In my ey experience I have used them for my mount in the past and also used to use them when overnight carp fishing to run lights and a 12v television so worked on low currents.

Steve

Hi  Steve.

While I currently don't have dew heaters, now that weather is getting colder it may be that I start to need them soon.

I have noticed the telescope gets pretty wet now. Although it hasn't been a problem as far as the optics are concerned.. yet.

Maybe I should just buy a leisure battery and build a box around it like you suggest....

Any thoughts on using that sort of setup?

John.

16 minutes ago, teoria_del_big_bang said:

Personally, I would sort of agree with both replies, which may sound odd as they are quite different.

In short:

• I suspect the jumpstarter will in effect be no real different to the skywatcher lead acid option.
• From my experience with them they will power a small mount and camera for a reasonable time , probably for at least 4 to 6 hours reliably - but all depends on whether it is just the mount and camera and how often you are slewing at fast rate which takes a lot more current, and that you are not also using dew bands and other bits on the 12V.
• I suspect it will last a number of years so long as you maintain its charge and when you have finished a session you put it on trickle charge till fully charged and when left in storage you take it out and trickle chage to fully charged every few weeks. But that will be no different with the Skywatcher version.
• A far better, but more expensive, option is something like Celestron Power Tank

Inside the starter will be a small lead acid battery similar to 17AH Battery and in my opinion is fine for powering a mount and I have used similar in the past with no issues.

I cannot tell for sure , without buying one and looking inside, but as it is a relatively cheap so called "Jump Starter" if it like the ones from Halfords I have had in the past it will not have a specialized high current battery inside but one very like the link which are still capable of high currents so will start most car engines if it is fully charged but do not tend to last too long if used a lot. But they seem to work fine as well delivering 1 to 2 A as you will require, so long as they are looked after properly and charged properly. 

To be honest although again I do not know I always assumed the Skywatcher Power Tanks  (which are now £99 from FLO Skywatcher Power Tank 17aH ) were just the same as the Jump Starters and would have the same batteries. But I could be wrong and would be nice to know from any owners that have had them apart if the batteries inside are any different.

BUT, as @Waldemar does say it is not ideal for several reasons .

Whatever, both the Jumpstarter and the Skywatcher are lead acid and do suffer from lowering in voltage as they discharge and will start off at 13.8 V  and will quickly drop to around 12 to 12.5 v and eventually will be a little below 12V as they approach being discharged. Again when I used these I never had issues either with mount or camera when even a little below 12V but I have read threads where people do have issues with the mount when slewing at 12v or below.

Also they need looking after in that they do not like being fully discharged and if left discharged for any length of time you will lose a lot of its potential and will not really be capable of providing 17AH anymore and if left a long while will become almost useless. They will also discharge themselves to some extent even when left in storage not being used so if you need to use it and have not used it for a month or so you may need to do a bit of a charge before using it if you want it's full potential.

A far better option is a  LiFePO4 battery, but you will pay more than £50  for something around 17Ah, but ultimately might save money as they will last many years longer and will be easier to look after (and they are a lot lighter if you are traveling with them.

Also I do agree with @Waldemar about the cigarette lighter connectors, totally useless and give too many problems with bad connections for astro use but so much equipment uses them.

 

Where are you wanting to use your scope ? Is it just from home or are you traveling to remote sites ?

If just from home why not use something like this Outdoor 12V supply Ideally housed in a waterproof housing that is large enough to stop supply over heating and also then connected via a Rcd unit.

Steve

Thanks for the replies.

I used to build and fly drones so I am used to the drill with charging/discharging/recharging etc.

I will only be using this when I travel to dark sites etc. Which realistically won't be that often.

I generally image from home, and I use an extension lead in a box, going back to the house and plugged into an RCD then.

27 minutes ago, Waldemar said:

The powersupply you linked to, is a jumpstarter, meant to provide a very high Amps output for a very short time to start cars...
What you need is a battery that can deliver a low Amp output for a long time. A totally different kind of battery, called deep cycle battery.
The best would be a LiFePO4 battery, which can deliver constant power until it is almost empty, while the lead-acid batteries you are mentioning drop below 12 Volts very fast and make your equipment not doing the things you want it to do.
The difference in price is not because it can be used for astro purposes, but because it is a totally different type of battery, with a far better output and also far longer lifespan.

Be aware that the so called cigarette lighter connectors are exactly that: to light cigarettes, not for constant power use. 
The plus connectors (tip) of the plugs are spring loaded and tend to work themselves out of the ports to make a bad or non contact when you least expect it.
I really don't understand why astro companies still use those 🤬 things for such expensive equipment. Must be economics...
Just use connectors that are made for the purpose of constant full contact.

Two answers, both completely different.

I know a lot of people use these types of multi-functional jump-starters to power their mounts. It was more of a question as to whether this particular one is ok, not so much whether jump-starters can be used.

Interesting that you should say not to use them at all.

Hi people. I'm here to pick your brains again. 

Would you think this is a suitable power supply to power my mount and camera in the field?

https://www.halfords.com/motoring/battery-maintenance/jump-starters/4-in-1-jump-starter-594335.html

It's got 2 cigarette lights type 12V ports, and a USB. It's 17ah.

I only have to power my camera and EQ5 synscan. I would think it should be plenty. 

And it's £50 quid as opposed to about £130 for the Skywatcher 17ah version...

Opinions, thoughts, alternatives are all very welcome.

SharpCap PA tool is great isn't it?

Just looked like clouds to me. 😞

There is someone selling one now on Facebook for £250. Is this a good deal?

6 minutes ago, JamesF said:

I really don't think so.  That was/is Dr Robin Glover.  Though he could of course be "Fearl0rd" at the weekends.

James

Ha! 🤣

My bad. Fearl0rd is the guy who coded the ASCOM driver for DSLRs.

2 minutes ago, tooth_dr said:

That looks neat.  Mine was just a circle, based on a cardboard template, and you can see the filter was threaded from the back, and still just cleared the mirror.

I think I might get that, and then buy an l-extreme 1.25". Whenever they are back in stock.

Found it!

https://www.thingiverse.com/thing:4306640

Fearl0rd? Isn't that the guy who coded SharpCap?

5 hours ago, tooth_dr said:

It is possible to fit a 1.25” filter inside the camera, between the T adapter and the mirror, I’ve tried it myself and it works ok.  I used a small 3D printed holder. 

That is very interesting. Especially as 1.25" filters seem to be cheaper than clip filters.

Have you had any issues with using a 1.25" filter? 

Do you recall where you got the adapter from? Or was it on Thingiverse or something?

25 minutes ago, tooth_dr said:

It's not a bad idea, but the problem is that its too small an opening for a 2" filter, and too large for a 1.25" filter.  You could make an adapter to hold the 1.25" filter housing into that space, but it would cause severe vignetting with the DSLR crop sensor.  An EOS clip filter as suggested above is a good idea.  It's not as versatile as you have pointed out, but it does the job it's intended to do very well.   I've learnt myself in astronomy that sometimes you can kill two birds with one stone, but more often than not it involves a significant compromise.

 

Hi there. Thanks for the clear reply. I just wasn;t sure of there was a filter size that would fit this thread. But it sounds like even if there was one it may be more trouble than it's worth to put a filter that far away from the sensor.

From what I've been reading it sounds like a clip-in filter will help with colour shift and possibly haloing as well.

The reason I've been enquiring about this is I have a NIkon APS-C which doesn;t have a lot of filters available for it. I am going to get a Canon instead, as these have a much wider range of clip ins to choose from.

On 18/11/2020 at 05:48, Chefgage said:

Have you thought about a clip in filter for your DSLR? I use this type https://www.harrisontelescopes.co.uk/acatalog/skytech-cls-canon-eos-clip-filter.html?gclid=Cj0KCQiAhs79BRD0ARIsAC6XpaWe5phCbxkfNit8tXskT4sv-PZJvdktHdJMhrfrDD0prSoQufeEAkIaAun8EALw_wcB

 

Thanks for the reply. Yeah, I have thought about a clip-in filter, but I'm just trying to work out how other people do it.

I think using a filter in the nosepiece is more versatile, as I could maybe use them for visual too.

Anyone have any idea?

Turn left at Orion is great, especially if you don't have a goto mount.