bobro

1 hour ago, AstroMuni said:

So is your mirror from the SW 130PDS?

The mirror was purchased from AstroBoot - it was listed as coming from a SW 130P. I understand the same parabolic mirror is used in the 130P and the 130PDS.

You're making a great start to imaging . My 130 reflector is a Meade Polaris - not much different from the Celestron 130 you are using. I purchased it a few years ago and have made a few mods to it to improve its imaging capabilities:

• Mirror exchanged for a SkyWatcher parabolic mirror 
• Focuser mount strengthened to take the weight of a DSLR initially (now holds a filter wheel and Altair 183M)
• Tube shortened to allow a DSLR to come to focus (not necessary for use with a dedicated astro camera)
• 1.25" Coma Corrector inside the focus tube

It would have been easier to start with a 130PDS, but not half as much fun working out the mods  🙂

The EQ2 mount made a useful start for imaging, especially after being modified for guiding. However, the lack of goto became a nuisance so the 130EQ now sits on a goto guided EQ5.

After a break with astrophotography for a while I'm now back having fun with the hobby, only recently starting to try out Siril and StarNet++. I use GIMP for processing.

You asked others using a 130EQ to post images. Below are some of mine from the last few weeks as I restart imaging. The M33 needs much more data (waiting for clearer skies), plus my Ha filter is rather old and produces large halos - hopefully to be upgraded before too long.

May seem a daft point, but the screw holding the mount down to the tripod may need slackening first before the mount is moved in azimuth using the adjusting screws. Otherwise a lot of force could be exerted on the pin, causing it to bend. Apologies if you have been doing this.

EQ2s have a tangent arm on the DEC axis for adjustment rather than a worm gear. That is why there is a limited range of movement. If too much force is used on the control rod it's possible the drive spindle connected to the control rod can bend slightly against the tangent arm and jam.

This thread shows the EQ2 in detail https://stargazerslounge.com/topic/319273-meade-large-equatorialeq-2-hyper-tuning/

I suggest loosening the nut as shown by the yellow arrow in the below image from the thread. That should free the drive spindle and allow it to be checked.

A small amount of mirror astigmatism perhaps? Tight mirror clamps can cause mirror astigmatism.

4 hours ago, ozcarlosa said:

Hi 

I am new in this topic and I found that the website guiding.web.fastmail.co.uk is down and I would like check your mod for DEC motor drive. Please, can you repost that information? 

Hi,

The website has been put back. Only the motor was used from the DEC motor drive (you can see it in one of the photos) as, for guiding purposes, it is only switched on briefly, with the polarity used to determine guiding direction. Guiding works pretty well in the DEC direction as there isn't significant backlash in the drive.

This was my first attempt at guiding an EQ2. My second attempt used an Arduino for the hardware interface connected to PHD2 for guiding on the same laptop as for capturing images.

9 minutes ago, Blakey said:

When you say considerable limitations of the EQ2 are you referring to it's stability ?

It's certainly rather wobbly, though the Meade version with tubular legs may be better than others. Other considerations relevant to astrophotography are: polar alignment (no RA axis polar scope so other methods must be used), load carrying capacity, no guiding in RA/DEC, no goto and a focuser that will deflect with the weight of a DSLR. The Meade Polaris 130 OTA (like others of this type) won't come to focus with DSLR. 

It depends on what sort of images you wish to take e.g. a webcam or dedicated astrocam (not cheap) can be used successfully with the Polaris 130 setup to take images of the Moon or some bright deep sky objects. DIY work can extend the capabilities to an extent.

It helps to understand the key difference between the Economy/Simple motor drive and the one with a handset: the Economy motor drive has a basic motor that is voltage driven and not accurately speed controlled. That's not good for astrophotography as the tiny speed control has to be tweaked (repeatedly) to try and track targets without streaking due to the motor not running at the required speed (it varies with battery voltage). This motor drive is aimed at observing where slow drift is not important.

The motor drive with handset has accurate speed control, hence it is better for astrophotography, subject to the considerable limitations of an EQ2.

EQ2 mounts from SkyWatcher and Meade are basically the same and will take either motor drive.

On 07/06/2021 at 17:15, stars420 said:

conpletely blank  Canon T3 1000d mod 130mm celestron Newtonian

Unless designed for imaging, 130mm Newtonian telescopes typically will not come to focus with a DSLR attached due to lack of inward focuser travel. Would explain the 'blank' images.

Looks to be a standard EQ2 mount.

The position of the RA flexible control relative to the eyepiece will vary depending on whether objects in the northern or southern sky are being viewed. Equatorial mounts are designed to be polar aligned to subsequently allow objects in the telescope's field of viewed to be tracked by adjusting only the RA control.

This can be a bit tricky to understand but there are lots of youtube videos explaining this. Here is an example with an EQ2 (note this is for the southern hemisphere - for the northern hemisphere the RA axis is aligned with the north pole): https://www.youtube.com/watch?v=1aailjnVZt8

Here is a Youtube video that may help: https://www.youtube.com/watch?v=6Y0gU1YrnFM

Move to Spain first!

2 hours ago, malc-c said:

Just bear in mind that the dual axis motor upgrade uses DC motors where as the goto upgrade uses precision stepper motors. 

The dual axis motors are stepper motors, it's just that they are very low torque and highly geared to allow battery power driving without too much current consumption. I successfully used them connected to an AstroEQ for guiding. However, the gearbox makes slewing much too slow, hence they aren't good for goto.

Some great things about the Moon are that it is easy to find and so bright that short exposure video imaging can be used with it. Many other DSOs, with the exceptions of planets, are dim and so require long exposure imaging. The dual axis motors, and mainly the RA motor, help with longer exposures though not with finding a target as they are too slow for goto. The dual axis motors can be used with guiding, though RA guiding mainly as DEC guiding isn't too accurate with the EQ5.

So I agree with @SMF that the RA motor is useful and a low cost introduction to longer exposure manually located imaging. Good polar alignment won't be necessary with your setup if non-motorised static as star trailing will limit imaging time. An RA motor can help provide images of around 60s or so (some can achieve longer) with reasonable polar alignment.

My EQ5 setup started with the dual-axis motors and AstroEQ for guiding, followed by replacing the motors with quicker stepper motors (twice) for belt driven guiding and goto, still with the AstroEQ.

Dual axis motors are a potential way forward without goto, though a SynScan upgrade for the EQ5 may be a better route, especially as this can provide goto before going for a guided setup.

I purchased the Meade 130 Polaris about 3 years ago. It has 2 screws to secure the eyepiece (I added a third for imaging purposes). The aim of the red dot finder can be initially set using the 2 screws that attach it to the scope tube. Following that the finder adjustment screws provide fine tuning, with subsequent accurate pointing. Of course not everyone likes a red dot finder.

It's a pretty good scope with an EQ2 mount having tubular legs, though still rather wobbly.

Are you sure you mean the Declination ring and not the Right Ascension ring? The RA ring can be rotated if the locking screw next to the small pointer is released.

I purchased one of these: http://ebay.co.uk/itm/223895728711 though from a different China based seller.

Collimation as delivered was terrible, though the black (silicone?) stuff over the collimation screws was easy to remove, allowing the laser collimator to be collimated by projecting it onto a wall whilst rotating the collimator and adjusting the screws.

A good purchase and did the job for my 2 scopes, which I thought were ok but turned out to be a bit off collimation.

10 hours ago, SStanford said:

I assume I can attach my dslr straight to the EQ5 similar to the Star Adventurer with an adapter?

They are both equatorial mounts and can carry a DSLR. The Star Adventurer isn't GOTO, which can turn into a serious disadvantage: I upgraded from a guided EQ2 to a GOTO EQ5 mainly for this reason.

An HEQ5 can make a great start to DSO astrophotography, especially where longer exposures and heavier carrying capacity are required.

When imaging from a balcony there can be a restricted view, plus in the UK good imaging nights are few. That means capturing what can be seen as quickly as possible. One way to achieve this can be to go for brighter objects and/or widefield targets. This tends to mean shorter exposures perhaps with a shorter focal length scope and therefore a less capable mount can meet the need.

One approach could be a Star Adventurer with a stock lens on your camera - good for widefield and shorter capture times. Also less sensitive to vibrations that could occur on a balcony.

Also, what targets (e.g. Moon, planets, Deep Space Objects)? Astrophotography from a balcony in a location where there could be local light pollution may be challenging, though it does depend on the target and imaging method.

A stretched version of the flat shows reasonably good collimation, but not quite spot-on.

@tooth_dr suggests taking a photo of the setup (camera and CC attached to focus tube). This will help with a check of spacing (someone else will need to check this as I don't use the Baader CC).

You could continue with a step-by-step check, with the camera next. When a 650D is astromodified the sensor is removed and needs to be refitted in the same alignment position. There are 3 screws holding the sensor - if they are not adjusted to the original position the sensor can be tilted, resulting in focus issues. To check this you could take a photo during daytime with a lens fitted to the camera. If sharpness of the image is good across the image the camera should be ok. Hopefully the camera will come to focus with a lens after being modified (may depend on the lens). Manual focus is probably best to use.

If the camera tests out ok, it could then be refitted to the scope without the CC and a star image made. The image should show coma on stars (like little comets) towards the 4 corners, but otherwise focus should be good across the image. 

Hope this helps.

If polar alignment is well off it can result in stars showing as streaks, not as round out of focus stars. 

Holes in the centre of stars with a reflector are due to the secondary mirror becoming apparent with the image out of focus.

With the CC removed, try taking a flat before imaging again. The resultant flat will show if the scope is collimated. The illumination source doesn't have to be too complicated e.g.  an evenly illuminated ceiling without bright light directly entering the scope (what I use) or an evenly lit sky with a piece of paper or similar across the scope to diffuse the light. An exposure of something in the region of 0.5 sec will do fine as the camera shutter won't have an effect at this exposure time (too short an exposure can mean the shutter travel will affect the flat).

You mention having cropped a lot of the image in the first post above. Even with cropping there is obviously something wrong with alignment as stars towards the bottom right are much less than sharp. With a coma corrector stars should be very much smaller.

I suggest going back to basics. That means removing the CC and ensuring the scope is collimated. A flat and also an image of stars will help to show this - post here if it helps. If all is well the CC can then be added and flats etc redone to check the setup. It then should be possible to find out what is causing the glow if it still appears e.g. by taking a dark/obscuring the viewfinder/turning off the screen.

Measuring the amount of spare focuser inward travel available with the ASI224mc camera is straightforward: remove the eyepiece and stick a piece of white translucent paper across the focuser eyepiece flange. Then focus on a very distant object (the Moon is perfect, even during the day. Not the Sun). When in focus the image will be seen in focus on the paper.

Now measure the amount of spare inward travel of the focuser. The flange to sensor distance of the ASI224mc is 12.5mm. Subtract this value (12.5mm) from the amount of spare inward travel previously measured. If the result is a positive value (very likely) the ASI224mc will come to focus with the scope.