Which mount to buy? Cem25p or Heq5.

[Petar b]

Which mount is better for astrophotography? iOptron cem 25p or Skywatcher heq5. I would use small refractor for imaging.

[StuartJPP]

In my opinion Skywatcher HEQ5 - much better software support (EQMOD) and a track record of it producing the goods.

 

[vlaiv]

+1 HEQ5, but this is based on limited experience (only used heq5 and not iOptron so no direct comparison) - it just works, have it, modded it (belt mod), for small frac it does not even need belt mod or hyper tuning (if you limit your resolution to 2"/pixel or above).

[pete_l]

I would agree. My HEQ5 + ED80 refractor simply "just works". No need to rip it apart, tweak anything, modify it, add extras (apart from the 0.85 FR/flattener and a power supply). Use a 50mm straight-through guider and QHY5-class cam, and you're laughing.

[Petar b]

Why would you recomend the heq5 over cem25p?

[Petar b]

People say that the polar finder is amazing on cem25p and has low periodic error od under 10 arc second.

[vlaiv]

I would not recommend heq5 over cem25p, I would just simply recommend heq5 for small refractor. Period.

Because it is tried and tested combination, and works. I can say that with confidence, it is not second hand, hear-say thing, it is first hand experience.

[Petar b]

The cem25p is lighter and has the same payload.

[vlaiv]

2 minutes ago, Petar b said:

People say that the polar finder is amazing on cem25p and has low periodic error od under 10 arc second.

I do base my recommendation on guided setup. I myself had issues with unguided HEQ5, but after modding it's now in range of +/-7 arc seconds for PE, and really smooth. I tend to use a bit heavier setup as my primary imaging rig (RC8" that gives me native 0.48"/pixel and 0.96"/pixel binned with my camera and no focal reducer), so max resolution that I would dare go with heq5 is 1"/pixel. With TS80 F/6 apo, it gives nice ~2"/pixel and I comfortably use 6-8s guide exposures with rms guide error in range 0.5-1.0" (good to bad seeing), more than enough for 2"/pixel resolution.

[ronin]

The CEM25P seems a bit unproven, it might turn out better but I think the answer is no-one is quite sure.

The CEM25 started from the ZEQ25, then this was replaced by the CEM25 - the oddity of the replacement to me was that they took back the ZEQ's then (strangely) manually filed the old ZEQ casing to make it accept the new CEM25 items, then sold them as CEM25's. So the early ones had all the marks of someone having filed the casing. Would have expected them to simply have had a supply of replacement casings.

Then the CEM25 disappeared, seemed to have been withdrawn again as no where had any. Then they reappeared under a slightly different name and that is how they are at present.

The original ZEQ25's seemed reasonable and you get the idea they made a new one that just wasn't as good.  Have heard the motors are or were a bit under torqued for the scopes/load. They may have changed but not sure.

I suspect they decided to update the mount but marketted them before the bugs were fully sorted. And that tends to worry people and be a killer for the item.

The HEQ5's do have problems and that seems to be in the electrical and firmware areas, although most occurances of this are on EQ5's but that could be as they are more common.

Sometimes I think they produce a mount like the CEM25P where the P stands for Precision, whereas many would prefer a CEM25R where R stands for Robust.

One other aspect I have noticed is that one retailer no longer stocks/advertises/sell the smaller iOptron mounts, and that includes the CEM25's. They have the 45's and the 60's but not the SmartEQ, CEM25, ZEQ30's (not sure if there is another but think there is or was). That tends to make me think Why would they drop a line.

Will say that read carefully all you see about any mount, the AVX is an example. One person said they would not even recommend the mount to someone they did't like, never mind anyone they did like. Then I read people saying What you want is an AVX as they are good mounts and ideal for what you want. Take your choice.

[StuartJPP]

I did briefly own a ZEQ25-GT and let's just say that I wish I never did. Although on paper it ticked a number of boxes, in practice it was a poor excuse for a mount. QC was abysmal and overall a total disappointment.

ZEQ/CEM/CEM-P...I'd wait for CEMP-FINAL version where they hopefully get it right.

I am not saying that they are all bad, but make sure you buy it from someone who has a good return policy.

[valefor]

11 hours ago, pete_l said:

I would agree. My HEQ5 + ED80 refractor simply "just works". No need to rip it apart, tweak anything, modify it, add extras (apart from the 0.85 FR/flattener and a power supply). Use a 50mm straight-through guider and QHY5-class cam, and you're laughing.

I have this exact setup and couldn't agree more. It just works. Heq5s and small refractors. Peas and carrots. 

[Petar b]

Why wouldn't cem25p and a small refractor just work?

[StuartJPP]

2 hours ago, Petar b said:

Why wouldn't cem25p and a small refractor just work?

Seems like you have already made up your mind?

Buy one and let us know how you get on with it.

[TareqPhoto]

Go with AZ-EQ5, end of story.